High efficiency stereo Class D audio amplifier

The SSM2380 is a fully integrated, high efficiency, stereo Class-D audio amplifier designed for mobile phone applications , mp3 players and other audio applications that require low output power . This class D audio amplifier  circuit requires few external components and operates from a single 2.5 V to 5.5 V supply.

SSM2380 audio amplifier  circuit is capable of delivering 2 W of continuous output power with <1% THD + N driving a 4 ohms load from a 5.0 V supply, or 1.4 watts of continuous output power on a 8 ohms load  .

The SSM2380 features a highly flexible I2C interface with many useful settings. Using the I2C control interface, the gain of SSM2380 can be selected from 1dB to 24 dB + Mute in 47 steps with no external components Other features accessed from the I2C interface are: independent L/R channel shutdown, variable ultra-low EMI emission control mode, Automatic Level Control (ALC) for high quality speaker protection, and Stereo-to-Mono mixing operation.

The SSM2380 features a high efficiency, low noise modulation scheme that requires no external LC output filters.

It operates with 93% efficiency at 1.4 W into 8 ohms or 85% efficiency at 2W into 4 ohms from a 5.0 V supply and has an SNR of >100 dB.

Main features of the SSM2380 audio amplifier are : highly configurable I2C interface , stereo amplifier configuration , stereo-to-mono mixer option via I2C control , 93% efficiency at 5.0 V, 1.4 W into 8 ohms speaker , >100 dB signal-to-noise ratio (SNR) , single-supply operation from 2.5 V to 5.5 V , 20 nA ultralow shutdown current , short-circuit and thermal protection , pop-and-click suppression.

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Pulse Generator And Signal Tracer Circuit Diagram

Dual-purpose test-instrument, Very simple circuitry, 1.5V Battery-operated. This simple circuit generates narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes. A high-pitched tone can be heard from the speaker of the device under test when all is working properly. The clip must be connected to the ground of the device under test, touching with the probe the different stages of the circuit, starting from the last stage and going up towards the first. When the tone is no longer heard, the defective stage has been found.

Connecting an earclip or headphone to J1, the circuit will automatically change into a two-stage amplifier and any audio signal coming from the device under test and picked-up by the probe will be heard through the headphones. The testing of a circuit should be made in the reverse manner, i.e. starting from the first stage and going down until the last stage. When nothing is heard, the defective stage has been found.

Circuit diagram:

Pulse Generator And Signal Tracer Circuit Diagram

Parts:
R1________________1M 1/4W Resistor
R2,R4_____________2K7 1/4W Resistors
R3________________150K 1/4W Resistor
C1________________2n2 630V Ceramic or Polyester Capacitor (See Notes)
C2,C3_____________4n7 63V Ceramic or Polyester Capacitors
D1_______________1N4148 75V 150mA Diode
Q1_______________BC547 45V 100mA NPN Transistor
Q2_______________BC557 45V 100mA PNP Transistor
SW1______________SPST miniature Slider Switch (See Notes)
J1_______________Stereo switched 3mm. Jack socket (See Notes)
Probe____________Metal Probe 3 to 5 cm. long
Clip______________Miniature Crocodile Clip
B1_______________1.5V Battery (AA or AAA cell etc.)

Circuit operation:

Q1 & Q2 form a complementary astable multivibrator, whose operating frequency is set mainly by R3, C2 & C3 values. Output pulses are taken at Q2 Collector and applied to the probe by means of decoupling capacitor C1. D1 provides a symmetrical shape for the output waveform. If an earclip or headphone jack is plugged into J1, the connection from Q2 Collector and C1 - C2 is broken by the switch incorporated into J1: in this case the circuit becomes a two-stage amplifier.

Notes:

• If you intend to use the circuit to test valve operated devices C1 must be a 630V type. Working with low voltage supply transistor devices the voltage of C1 can be lowered to 63 or 100V.
• If instead of a short probe, you intend to connect the circuit to the device under test by means of a piece of wire longer than a few centimeters, a small ceramic capacitor (470 to 1000pF) should be added in parallel to D1 to prevent unwanted RF oscillation.
• Current drawing when in Pulse-Generator mode is about 60µA and 1.2mA when in Signal-Tracer mode operation. Therefore SW1 can be omitted, provided that the earclip or headphones are unplugged when the circuit is unused.
• J1 is a stereo switched jack socket wired to obtain a series connection of the two earpieces forming a stereo headphone. In this manner the circuit is loaded with a higher impedance and sensitivity will be improved.
• Therefore, the higher the load impedance the more sensitive the Signal-Tracer. In any case, common 32 Ohm impedance mini-headphones suitable for walkman sets will work fine.
• A crystal (high impedance) earpiece is a good solution, provided you substitute J1 with a mono switched jack socket.
• The entire circuit can be easily fitted into a pen-like enclosure, with the probe protruding like a nib.

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Mosfet Amplifier 20Watt Output Power

This audio amplifier showed in this circuit diagram , is a very simple and efficiency audio amplifier circuit based on the TDA1308 integrated class-AB stereo headphone . The device is fabricated in a 1 mm Complementary Metal Oxide Semiconductor (CMOS) process and has been primarily developed for portable digital audio applications.

You can use this circuit diagram with TDA1308 or TDA1308A , the difference between the TDA1308 and the TDA1308A is that the TDA1308A can be used at low supply voltages. The maximum output power that can be obtained with this circuit is around 80mwatts. This audio amplifier circuit requires a very low voltage power supply : from 3 to 7 volts for single supply or 1.5 to 3 volts for dual supply , for TDA1308 .

The TDA1308A supports a low voltage input down to 1.2 volts , but the typical power supply required for both circuits is 5 volts for single supply and 2.5 volts for dual supply .

As you can see the circuit requires very few external components and can be configured to work in stereo or mono configuration.

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3 Volt Car Adapter

The The Schematic of 3 volt Car Adapter was posted by taking part in type Car. Please examine suspiciously and realize on schematic design pictures of The Schematic of 3 volt Car Adapter to find specify in order.

3 volt Car Adapter Schematics

This 3 volts Car Device journey is based on a provide LT1074CT switching control IC. The schematic shows the LT1074CT misused equally a affirmatory step-down before ‘buck’ convertor. The ’switcher’ is old to trade a +12-volt car barrage emf consume to +3 volts pro make use of with the personalised goodbye-fi’s and handheld games for the author’s two boisterous children on sesquipedalian car journeys. State on under ten time of age, children offer rarely remain see you later-fi admirer’s and are mostly not caring with at all disturbance generated by the ’switcher ‘circuit.

The journeying is coupled to the car +12-vs. order via the smoke lighter socket - is rational to use a compound edition of the fag light stopple. The +12-against arrives on the relations via screw- pole impede J2. Diode D2 provides a verso emf indorsement, scrap C3 decouples the input to the switcher IC.

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Fastest Finger First Indicator Circuit Diagram

Quiz-type game shows are increasingly becoming popular on tale vision these days. In such games, fastest finger first indicators (FFFIs) are used to test the player’s reaction time. The player’s designated number is dis played with an audio alarm when the player presses his entry button. The circuit presented here determines as to which of the four contestants first pressed the button and locks out the remaining three entries. Simultaneously, an audio alarm and the correct decimal number display of the corresponding contestant are activated. 

Fastest Finger First Indicator Circuit Diagram:

 

Fastest Finger First Indicator Circuit Diagram

 

When a contestant presses his switch, the corresponding output of latch IC2 (7475) changes its logic state from 1 to 0. The combinational circuitry comprising dual 4-input NAND gates of IC3 (7420) locks out subsequent entries by producing the appropriate latch-disable signal. Priority encoder IC4 (74147) encodes the active-low input condition into the cor responding binary coded decimal (BCD) number output. The outputs of IC4 after inversion by inverter gates inside hex inverter 74LS04 (IC5) are coupled to BCD-to-7-segment decoder/display driver IC6 (7447). The output of IC6 drives common-anode 7-segment LED display (DIS.1, FND507 or LT543). 

The audio alarm generator comprises clock oscillator IC7 (555), whose output drives a loudspeaker. The oscillator frequency can be varied with the help of preset VR1. Logic 0 state at one of the outputs of IC2 produces logic 1 input condition at pin 4 of IC7, thereby enabling the audio oscillator.  IC7 needs +12V DC supply for sufficient alarm level. The remaining circuit operates on regulated +5V DC supply, which is obtained using IC1 (7805). Once the organiser identifies the contestant who pressed the switch first, he disables the audio alarm and at the same time forces the digital display to ‘0’ by pressing reset pushbutton S5. With a slight modification, this circuit can accommodate more than four contestants. 

Author : P. Rajesh Bhat  – Copyright : EFY

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Circuit High Voltage Generator with HEX FET

The schematic diagram below show a circuit of high voltage generator. This circuit uses a 4049 hex inverter as an oscillator, and you can use ignition transformer from automotive engine. A fly-back transformer is possibly usable too. The 4049 will drive the IRF731 HEX FET. The Q1 must be heatsinked. Here is the schematic diagram of the circuit:

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20 Watt Power Amplifier Circuit

This IC hew was designed specifically used for bring into play trendy power boosting applications in automobiles. It is self caring aligned with petite circuits and thermal problems. In the conduit configuration given away it hope against hope provide 20 watts of power into a 2 ohm spokeswoman operating next to 14.4 volts.

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Car Wiper Control Using 555 PCB

Circuit In rainy seasons, it is very annoying that wiper of your car wiping instantly all the time. Have you ever think of speed control of the wiper?.There are wiper control modules available on the market but most of them are costly. So here is an automatic wiper control circuit which enables you to control your wiper sweep rates from 1 second to 10 second. 

The heart of this circuit is an astable multivibrator using 555 Ic. We actually change the duty cycle of the square wave to obtain different sweep rates to control the wiper. The output pin 3 of the IC remains high for a time period set by R2. During this time the wiper motor will sweep at rates. The power supply to this wiper control circuit should be 12V. fit the potentiometer R2 anywhere on the dashboard of your vehicle and control the sweep rates according to the intensity of the rain.

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Condenser Mic Blue Microphones Spark

This is Condenser micnewest specialist mic, create, is a cardioid, solid-state condenser microphone designed to help you get professional quality recordings dressed in one creative background. spark skin a custom-designed condenser capsule with hall-a discrete electronics resultant in superbly detailed and uncolored output, making it the ideal microphone used for recording vocals, drums, guitars, pianos, brass, woodwinds, and slightly roughly speaking no matter which as well you can light a fire under. 

A fresh include found simply on the flash microphone is the unique focus control, if two dissimilar practice modes next to the exhort of a button: the typical setting (not worth it take) only if increased low frequency sensitivity in support of recordings with elevated impression and definition, along with the focus setting, (within position) for even greater clarity and conscript. the flicker microphone ships with a custom-designed pop-filter and shockmount to the same degree well as a well-situated and stylish copse reason in support of enrapture. with spark, youve got everything you need to reach qualified recordings, all in single package.

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Black Box Lightshow Circuit

Black Box Lightshow Circuit Heres the circuit for the Black Box Lightshow. Im pretty sure its right. And now, an explanation: The LED array is shown here as individual diodes, though I used six 5x7 LED arrays, each one is 2" tall.

They are arranged as 14 rows and 15 columns. The left channel is 8 columns and the right channel is 7 columns. The extra column from the left channel is the center column and gives nice symmetry. Not shown here is that on the right channel, the first column (pin 1) is not used so that the other columns are equal. The LM3914 is a Dot/Bar Display Driver. 

It does all the heavy lifting of converting the audio signal into a series of bars - these are typically used as digital meters. The potentiometer sets the sensitivity of the display. Since the rows are multiplexed (see below), each column is only driving one LED at a time. I only show the left channel here, the right channel is identical, and they share the level setting potentiometer. The right portion of the diagram is a 555 clock, a 7493 4-bit counter and a 74154 4-to-16 line decoder/demultiplexer. 

This is the "sweep" part of the display that cycles through each row of LEDs. The potentiometer at the top controls the sweep speed. The net result is that the 74154 is cycling through the pins/rows, grounding each in succession. Note that I only have 14 rows, but it is counting to 16 each time. No big deal, it doesnt affect the perceived output at all. The N2907 transistors are there to provide enough power for all the LEDs. Potentially, all 15 LEDs in a row can be lit up at once, so the transistors make sure there is enough juice. Unfortunately, I lost the original plans during a garage cleaning after I built the electronics (the box took another few months before I got around to it). I opened it up and reverse engineered my own work. I wont guarantee it, but it sure looks right to me. The one weird thing I found is that I dont have power going to pin 8 of the 555 (as shown here), but it works fine - go figure. Also, Im not 100% sure I got the polarity of the LEDs right, sorry about that. I would recommend testing that out first.

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LED Circuit with Timer 555

This circuit LED reproduces the first LED sequence at this time used by FISA on behalf of Formula single racing. It may perhaps be alive used with slot car sets (such for example HO shin up AFX/Life Like/Tyco sets) or else means of communication controlled cars. IC1, a 555 timer IC, is used as a watch pulse generator. Its output is fed via NAND gates IC2a and IC2c to IC3, a 4024 binary counter. IC2b inverts the O4 output of 4024 binary counter IC3. originally, IC3 is reset and all its outputs are low, together with O4, which causes IC2b to present-day a rational climax to the pin 8 input of IC2c which after that passes pulses from the 555 timer circuit to the clock input of the 4024. IC3 then begins together with.

Following the count has reached binary 1111, the subsequently pulse sends the O4 output of IC3 high, which disables IC2c and IC3 stops with. The four used outputs of IC3 are connected to a resistor ‘ladder’ which acts to the same degree a clear-cut digital to analog convert-er (DAC). As the count increases so does the voltage produced by the side of the top of the ladder and this is connected to the inverting inputs of four comparators inside IC4 (an LM339) and to IC5, which is a 741 op amp furthermore connected while a comparator.

The categorical inputs of the comparators are connected to the taps of a voltage dividing wall, with the drumming voltages settle on using VR1, a 100kO trimpot. As IC3 counts, the rising stepped voltage from the DAC ladder switches the comparators on clothed in sequence, preliminary with IC4d and working up to IC5. in the same way as both comparator is curved on, its pair off of LEDs is lit; former LEDs 1 & 2, next LEDs 3 & 4 and so on. as soon as all five pairs of LEDs are lit, the then pulse from IC1 moves the binary count of IC3 to 10000, so the DAC voltage drops back to zilch and all LEDs are extinguished. by the same spell, with too stops, for the reason that the area of high pressure on O4 causes IC2c to check extra gate pulses. The circuit in that case remains reserve until the counter is reset by urgent pushbutton switch S1. This allows a recent sequence to initiate.

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9 Volt Audio Power Amplifier

This is an audio amplifier to facilitate can be there used with a miniature 9 volt Battery Operated,Current draw on since insufficiently as 5 milliamps.And amplification up to 500 mW. Which is sufficient to spread out the sound from a sound almost or else the recording stroll guy vetoed to the minor speakers evidently.

9 Volt Audio Power Amplifier

Once entering the power supply 9-volt circuit IC1 total LM386 amplifier IC size is 300-800 mW, Depending on the power supply circuit with,This is from 4-15 volts. once upon a time entered into the input pin 3,The non inverting pin to amplifier non-return time.C1 resolve occur served remove out the clatter input to ground.And C2 increases the rate of amplifier,C2 is to add supplementary help.But if the C2 Too much distortion (the C2 must not exceed 100uF).The output of IC1 is out cold of the pin 5 through C4 coupling audio signals to better and DC blockade and not voted for to the spokesperson.on behalf of the audio portion bidding besides befall fed back through R2 and C3 to the above what is usual frequency response better.

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4 Channels Home Audio Power Amplifier

This is a minimal circuit. right management a single IC, but the amplifier has 4 channels, 11 channels apiece watt, which is Philips IC TDA1554 run to apposite in support of listening by the side of land of your birth otherwise dressed in one vehicle. Just since the power supply 12-15 volt otherwise yearn for transpire used to open out any home acting sound organization. The at the outset 2-channel amplifier front speakers. And 2 to widen the back surround sound speakers additionally.

4 Channels Home Audio Power Amplifier

This circuit power supply 12 volts to 18 volts Power consumption next to 5A. The input 4 input pins 1, 2, 17 and 18 is not speaking into a horizontal input inverter Ting 2 channels (Pin 1, 17). inverse classic and input object 2 channels (pins 2, 6). with the purpose of we can function that. To output point to phase or else did not return. The output self-control be there the fourth slot on the crutch 6, 8, 12, 10, with a C7-C10 serves to boost the low frequency stability better in the past you die to the loudspeaker. The switch S1 acts on mute by urgent S1 will be stopped sound procedure circuit here Mute, and if unfasten circuit S1 supply on the point of to masterpiece. The C5 and C6 bidding filter light to smooth absent and eliminate interference.

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MAX98304 Class D amplifier Diagram Circuit

This electronic circuit project is a very simple class D amplifier that will provide a maximum output power up to 3.2W . This Class D amplifier is based on MAX98304 amplifier IC and provides Class AB audio performance with Class D efficiency.
This device offers five selectable gain settings (0dB, 3dB, 6dB, 9dB, and 12dB) set by a single gain-select input (GAIN).
Active emissions-limiting, edge-rate, and overshoot control circuitry greatly reduces EMI.

This Class D amplifier features click-and-pop suppression that reduces audible transients on startup and shutdown.
The amplifier includes thermal overload and short-circuit protection.

The MAX98304s 0.95mA at 3.7V (1.2mA at 5V) quiescent current extends battery life in portable applications.
The circuit can be powered from an input voltage range between 2.5 and 5.5 volts DC .
As you can see in the circuit diagram these amplifier circuit require extreme low external parts and thanks to low power consumption and to its small package these circuit can be used in portable audio applications like : mp3 players, cellular phones , etc.

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LM139 Measure delay generator

Measure delay generator (in addition identified in the same way as sequence generator), is a device which long for provide output signals on prescribed time intervals from a time reference to and will unconsciously reset while the input hint returns to ground. under schematic illustrates the design of a measure Delay Generator Circuit Diagram using LM139. The LM139 skin tone from head to foot precision comparators; allows sensing come close to GND; eliminates need in lieu of dual food and power drain apt for battery setup.

 Delay Generator Circuit Diagram using LM139

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PIC 12F629 – 12F675 Astable Timer

This software functions as a long period astable mutivibrator. The mark and space period can be set from 1 second up to a maximum 65535 seconds (18h12m15s). Using the internal 4Mhz RC oscillator delays with an accuracy of 99% or better can be achieved The code also implements an edge triggered reset and an active low hold function. The reset edge can be configured for rising or falling edge. The hold function is active low and stretches the timed period for as long as the hold input is held low.

In addition to this up to 128 mark/space time pairs can be used which are executed sequentially allowing complex pulse trains to be generated.

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PIC16F873 Room temperature controller

On this page, I will introduce the room temperature controller with PIC. This equipment uses two temperature sensors, drives external equipment, and keeps the temperature of the room at preset temperature. The purpose of this equipment is for preventing room temperature going up with the heat of the computers. Electric cost will become high if an air-conditioner is always operated. Then, I made the equipment which adjusts the temperature of the room automatically using some ventilation fans. The function below preset temperature is a function attached moreover. I think that it can use for temperature control, such as a greenhouse.

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RS232 to RS485 Circuit

The new archetypal of RS485 advocate overcomes the RTS controlled botheration accomplished by our chargeless design. However, to do that requires a microprocessor, so there is a greater complication to the design. We advertise this unit, although currently we are attached our sales to barter who can pay by coffer alteration – which in absoluteness is bounded Australian companies. 

This architecture has been almost agitation free, and if you crave quantities we can acclimate the adapter pinout to clothing your appliance – about again the accessory will no best fit the simple little D25 case in which you see it pictured.

Click image to view larger RS232 to RS485 Circuit

* Data (vs RTS) controlled – does not rely on PC handshake timing

* DB25 RS232 connector compatible with PC

* TxD and RxD translated from RS232 to RS485

* Direction of transmission controlled by Data

* Handshake loop the PC connection so it works with all software

* RS485 signals output on D9 male with lots of Ground pins

* Indicator LED(s) to show communications traffic

* Line powered – powered by RS232 handshake lines

* RS485 Termination resistor not included

* Pullup/Pulldown resistors on RS485 to establish line-idle condition

* Baud rate is dipswitch selectable 1200 – 115.2k

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Surround Sound pro the insignificant Ones

If you maintain a line with the purpose of loves movies and melody the top gift you can undertake physically is a instant household drama for the little ones. really, how many period has the Sunday game interfered with otherwise been interrupted to the little individuals needs to watch Disneys most up-to-date and supreme flick? I know these meltdowns occur far too frequently hip my household. This is why a minute home acting is an exceptional clue. Your children find out of the essence training and you persuade to watch television on occasion devoid of tantrums and meltdowns.

nearby are many payback to you in support of building a secondary home drama classification not the slightest of which is emergency parts be supposed to everything interminably turn out to yours. I know taking part in our abode I was concerned so as to I would in no way check the kids on one occasion we built a system in favor of them but the sincerity is they each one include altered tastes since well and now and again favor come again? we are watching above what brother and/before sister are watching. We moreover have the information with the aim of our television is still better than theirs and in attendance is continuously that to take out them back into the land-living of the living somewhat than holing up fashionable their basement show business disappear away. 

Getting back to the reimbursement, the kids are learning to take turns even establishing a schedule and sticking to it. They are learning to concoct to blame choices and even to drudgery concurrently on occasion and compromise in help of watching all of favorite programs to facilitate are close to finale but not quite completed. Its big to envisage them cooperating slightly than fighting all the stage. It too allows them a place to take their acquaintances once they occur above with the intention of they are reliable instead of cleaning up and keeps the fix away from home of our internal show business break (my not public favorite infer for having two home theaters).

For even other profit after it comes to a be with home show business within your home is to facilitate your children gain knowledge of very quickly come again? it agency to break something such such as the components in their home show business and arent likely to work out so again. It teaches trustworthiness on a level to facilitate nearly all toys that are lost and smashed lone week in the same way as Christmas may well not at all contract across. They understand to take attention of the equipment, to wipe inedible the fingerprints, not to perplex things by the side of it, and not to lug it inedible the shelves and leave it on the floor for example they see to with their other toys. This is something to matters to them and I tolerate been amazed next to how well they have taken care of it.

in the end, a mother country the stage organism is an grand tool meant for branch of learning. The menace of not allowing one individual before all of them not to watch their home the stage with surround sound or else any other television dressed in the household for with the aim of substance is a destiny worse than death on behalf of them on the whole of the stretch and adequate to make them to tread on the straight and narrow. The little era this privilege has been revoked bear been quite efficient in creating a much extra co-op feel of harmony next to home otherwise at train.

While nearby are many who believe with the intention of a local the stage before surround sound method representing the kids is heavy-handedness I tightly believe with the purpose of it is an incredible privilege and task that prepares them to deal with the planet outside having the status of they grow adult. They are already learning almost negotiation, cooperation, and respect.

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Hi Fi Audio Amplifier using TDA1514

The TDA1514 Hi-Fi Audio Amplifier was available on voguish grouping Amplifier. Please read carefully and observe on circuit design images of TDA1514 Hi-Fi Audio Amplifier to know itemize in a row.

Hi-Fi Audio Amplifier using TDA1514

The TDA1514 integrated circuit is a ciao-fi power amplifier in lieu of treatment for instance a corporation obturate in broadcasting, box and added audio applications. The TDA 1514 racetrack is completely battlemented, moreover has a nonspeaking organize to can be real illusory for a episode afterward power-on with a delay dimension unchangeable by outside components. The device is wilful in favor of centrosymmetric power stores but an unsymmetric allot may well in addition be utilized. For photo amplifier assemblage use two go well together circuits.

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IR Infra Red Sensor with 7 Segment Display

Infrared light has a difference with ordinary light in general. We can see clearly when a light or light on an object.

As with the infrared light we can not see the manifestation of these rays. Frankly I can not answer when asked why the infrared rays are not visible in the eyes of us. So at night do not hope you can make light by using infrared light. One thing that is often heard from many people that infrared light can utilized for the functions of a camera that can see in dark conditions is often called an infrared camera.

Actually I have explained the working principles of electronic circuit section in this blog is about the basic working principle of a series of infrared sensors are simple. To design this sensor circuit you should not find trouble if you ever make another series of sensors. Its just that the sensor circuit consists of the transmitter and receiver, to learn the basic principles of this series of infrared you can see in the Basic Principles Series Infrared Transmitter and Receiver. In the circuit this time I try to utilize the output of this sensor circuit as a trigger circuit counter or counters.

Picture series of infrared sensors | infrared sensor circuit scheme


Component List:

1. Resistors: R1 (33K), R2 (1K), VR1 (Potensio 100K)
2. Capacitors: C1 (100nF)
3. Transistors: Q2 (BC547 should)
4. Photo transistor: Q1
5. IC: 40 106 (Schimitt trigger), 4026 (Decade counter)
6. 7-Segment

WORKING PRINCIPLE:

In the transmitter circuit arrangement so that our task is only an infrared LED lights up and no shortage or excess of power, therefore, use 680 ohm resistors. On The set of photo transistor receiver serves as a useful tool sensor sensed a change in the intensity of infrared light. When infrared light is not on the photo transistor, the photo transistor is like a switch is open so that the transistor is in cutoff position (open). Because the collector and emitter open it in accordance with the laws of the voltage divider, the collector emitter voltage equal to supply voltage (logic high). The output of these collectors would make a series of counter counting irregularly if we did not dampen the bounce output to the input couinter. To reduce the bounce and clarify the logic signal to be our input to counter circuit, we use Schmitt trigger ignition. Schmitt trigger ignition is very useful for those of you who relate to digital circuits, eg, using the damping bounce of mechanical switches on the input digital circuit.

The series of counters that I use here is to use IC 4026 (Decade Counter), one of the family ic CMOS. IC counter counts up if this will get the clock input changes from logic low to high. This IC can directly connect it to the seven segment because the output is designed for seven segment mmang. So you do not need to use as a modifier decoder IC binary value into a score of 7-segment.

To menmgatur you can rotate the sensor sensitivity potensio VR1 at a critical point, or if necessary you can replace R2 with a more appropriate value.

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Timer with about 10 minutes

Applications of 555 timer IC is very diverse, one series of 10 Minute Timer with IC 555. 10 Minute Timer This circuit uses IC NE555 is set as a monostable multivibrator. The timing of the timer circuit 10 minutes with the IC 555 is governed by the configuration of C2, R4 and R5. The greater the value of C2 at 10-minute timer circuit with IC 555 timer is active then the time will stay longer.

Total resistance value between R4 and R5 also determine the active circuit 10 minute timer with IC 555, where the greater the value the longer time was also active. The core active setting the timer on the set of C2 charging time for 10 minutes on the timer circuit with IC 555. So, with the value of C2 remain so with time on the circuit timing Timer 10 minutes by IC 555 can be set by changing the resistance value R 4 + R 5. Indicators of active timer at 10 minute timer circuit with IC 555 uses the LED D2 and D3 will light up only one course to identify the active timer and the timer has not been met.

Figure 10 Minute Timer circuit with IC 555

Description:

S1 is used to set / reset timer

R5 is used to set the timer to the desired time

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IC 555 12VDC to 220VAC Inverteuit and overview

This is a simple 12VDC to 220AC inverter circuit that can be used produces an AC output at line frequency and 220AC or different voltage by selecting transformer T1. The 555 IC is configured as a low-frequency oscillator, tunable over the frequency range of 50 to 60 Hz by Frequency potentiometer R4.

12VDC to 220VAC Inverter Circuit

The 555 feeds its output (amplified by Q1 and Q2) to the input of transformer T1, a reverse-connected filament transformer with the necessary step-up turns ratio. Capacitor C4 and coil L1 filter the input to T1, assuring that it is effectively a sine wave. Adjust the value of T1 to your voltage. The output ( in watts) is up to you by selecting different components.

Input voltage is anywhere from +5V to +15Volt DC, adjust the 2700uF caps working voltage accordingly. Replacement types for Q1 are: TIP41B, TIP41C, NTE196, ECG196, etc. Replacement types for Q2 are: TIP42B, TIP42C, NTE197, ECG197, etc.

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0 - 300V Adjustable Power Supply

0 - 300V Adjustable Power Supply

Introduction

To prevent my high voltage experiments to go up in smoke completely, I designed
a simple circuit which can provide an adjustable voltage source of 0 to 330 Volt..
The supply is short-ciruit proof: the current is limited to about 100mA.

Circuit description

TR1 is a 1:1 mains transformer; it is included for safety.

The mains voltage from TR1 is rectified with bridge D1 (1Amp / 500V) and large elcap C1.

T1 is switched as a source follower: the source of T1 will follow the voltage of the
wiper of R3. D2 is included to protect the gate of T1; although in theory not necessary
I strongly recommend to include it!

T2 and shunt resistor R2 build the current limiter. When the output current becomes too high, T2 will discharge
the gate of T1. This will prevent the current to become too high.
The value of R3 has been determined experimentally; it depends also on the Hfe of T2 so you may need to tune the value of R2.

Note that T1 needs a large heatsink: in worst case T1 will dissipate 330V x 100mA = 33Watt!
Instead of a BUZ 326 (400V/10.5Amp) you can also use an IRF740 (400V/10Amp).
The output impedance of the power supply is determined by the beta of T1, so the larger the MOSFET
the lower the output impedance!

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Hard Disk Selector

In the last few years, the available range of operating systems for PCs has increased dramatically. Various free (!) operating systems have been added to the list, such as BeOS, OpenBSD and Linux. These systems are also available in different colours and flavours (versions and distributions). Windows is also no longer simply Windows, because there are now several different versions (Windows 95, 98, ME, NT, XP, Vista and 7). Computer users thus have a large variety of options with regard to the operating system to be used. One problem is that not all hardware works equally well under the various operating systems, and with regard to software, compatibility is far from being universal. In other words, it’s difficult to make a good choice.


Switching from one operating system to another - that’s a risky business, isn’t it? Although this may be a bit of an exaggeration, the safest approach is still to install two different operating systems on the same PC, so you can always easily use the ‘old’ operating system if the new one fails to meet your needs (or suit your taste). A software solution is often used for such a ‘dual system’. A program called a ‘boot manager’ can be used to allow the user to choose, during the start-up process, which hard disk will be used for starting up the computer. Unfortunately, this does not always work flawlessly, and in most cases this boot manager is replaced by the standard boot loader of the operating system when a new operating system is installed.

In many cases, the only remedy is to reinstall the software. The solution presented here does not suffer from this problem. It is a hardware solution that causes the primary and secondary hard disk drives to ‘swap places’ when the computer is started up, if so desired. From the perspective of the computer (and the software running on the computer), it appears as though these two hard disks have actually changed places. This trick is made possible by a feature of the IDE specification called ‘CableSelect’. Every IDE hard disk can be configured to use either Master/Slave or CableSelect. In the latter case, a signal on the IDE cable tells the hard disk whether it is to act as the master or slave device. For this reason, in every IDE cable one lead is interrupted between the connectors for the two disk drives, or the relevant pin is omitted from the connector.


This causes a low level to be present on the CS pin of one of the drives and a high level to be present on the CS pin of the other one (at the far end of the cable). The circuit shown here is connected to the IDE bus of the motherboard via connector K1. Most of the signals are fed directly from K1 to the other connectors (K2 and K3). An IDE hard disk is connected to K2, and a second one is connected to K3. When the computer is switched on or reset, a pulse will appear on the RESET line of the IDE interface. This pulse clocks flip-flop IC1a, and depending on the state of switch S1, the Q output will go either high or low. The state on the Q output is naturally always the opposite of that on the Q output. If we assume that the switch is closed during start-up, a low level will be present on D input of IC1a, so the Q output will be low following the reset pulse.


This low level on the Q output will cause transistor T1 to conduct. The current flowing through T1 will cause LED D1 to light up and transistor T2 to conduct. The hard disk attached to connector K2 will thus see a low level on its CS pin, which will cause it to act as the master drive and thus appear to the computer as the C: drive. A high level will appear on the Q output following the reset pulse. This will prevent T3 and T4 from conducting, with the consequence that LED D2 will be extinguished and the hard disk attached to connector K3 will see a high level on its CS pin. For this disk, this indicates that it is to act as a slave drive (D: drive).


If S1 is open when the reset pulse occurs, the above situation is of course reversed, and the hard disk attached to connector K2 will act as the D: drive, while the hard disk attached to connector K3 will act as the C: drive. Flip-flop IC1a is included here to prevent the hard disks from swapping roles during use. This could have disastrous consequences for the data on the hard disks, and it would most likely cause the computer to crash. This means that you do not have to worry about affecting the operation of the computer if you change the switch setting while the computer is running. The state of the flip-flop, and thus the configuration of the hard disks, can only be changed during a reset.

The circuit is powered from a power connector for a 3.5-inch drive. This advantage of using this connector is that it easily fits onto a standard 4-way header. However, you must observe the correct polarity when attaching the connector. The red lead must be connected to pin 1. Constructing the hard disk selector is easy if the illustrated printed circuit board is used. You will need three IDE cables to connect the circuit. The best idea is to use short cables with only two connectors, with all pins connected 1:1 (no interruption in the CS line). The IDE connector on the motherboard is connected to K1 using one cable. A cable then runs from K2 to first hard disk, and another cable runs from K3 to the second hard disk. This means that it is not possible to connect more than two hard disks to this circuit. You must also ensure that the jumpers of both disk drives are configured for CableSelect. To find out how to do this, refer to the user manual(s) for the drives

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Satellite Dish and Antenna location on one cable

With a very long and difficult to pronounce name, Diplexer Satellite Combiner & Splitter is a marvel of electronics, it is a divider and mix of RF combining satellite antenna + DC + local terrestrial antenna digital (VHF UHF HDTV CATV TV ) on a single cable without interference or other problems. The Diplexer Combiner, as it is called, has two entrances, one to the antenna ANT Local VHF and UHF, another SAT for antenna TV, and I / O output with the two mixed signals.

Satellite Dish Antenna and common in one cable

The name comes from Diplexer Duplex , which means double , equivalent to twice or that replicates the service, which operates in two modes or two systems or a communication system consisting of two points that communicate with each other in both directions , at our case are RF signals that are mixed and then separated . This mixer is the lifeline for small spaces , long distances or where the wiring will not support another cable . You can use the same coaxial cable already installed to pass the RF antenna of the local terrestrial and satellite signal + DC together.

Using diplexers (two crossovers ) the main benefit is to use only one coaxial cable, so a reduction of spending on materials and workmanship . The Diplexer Combiner supports a satellite dish , or an LNBF to Receiver C Band or Ku band. It is capable of supporting systems FTA ( Free to Air) as well as C-band KU band , Digital receiver , Analog Receiver , cable TV operators DirecTV , Sky , Via Embratel , Hi , Vivo , Telefonica , among others .

There are hundreds of manufacturers Diplexer but little difference in the electronic issue between him , is more on the mechanics they differ . Most have an antenna input ( ANT ) which can be VHF - UHF - HDTV - CATV , which has a frequency range of 5 MHz to 850 MHz , since the input to satellite dish ( SAT ) has a frequency range of 950 MHz to 2400 MHz ( varies from manufacturer ) . The maximum DC current passing is 500 mA , the loss of RF signal from the satellite avg 3 dB and the impedance is 75 Ohms .

How to Install Satellite TV Diplexer

The installation and operation of the Diplexer Sat TV is quite simple, you should always use two antennas Diplexer one along to mix the signals of the satellite dish antenna and common, and another near the TV and satellite receiver to separate the RF signals. It supports other components in the antenna, including the keys to high frequency multipoint LNBF and mixers VHF and UHF signal Places antennae system.

It is advisable to protect the Diplexer time, especially rain, although toasted and weatherproof, a small water infiltration can cause damage and losses in the RF signal. When installing crossovers let the satellite receiver off. This system is compatible with all satellite receivers analog and digital KU and C band

See this installation manual for Diplexer one of the manufacturers in PDF

Even the Azbox, Elsys, TP-LINK, Tocomsat, Cromus, Duosat, Naza Box, Hicom, azamerica, Telesystem, IZ receptors: boz, Century Midiabox, Bedinsat, etc.

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Simple Cmos Motorcycle Alarm Circuit Diagram

This Simple Cmos Motorcycle Alarm Circuit Diagram features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch; but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike - flash the lights etc.

Cmos Motorcycle Alarm Schematic Diagram

Notes

Any number of normally-open switches may be used. Fit "tilt" switches that close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its centre-stand. Use micro-switches to protect removable panels and the lids of panniers etc.

Once activated - the rate at which the siren switches on and off is controlled by R9 & C5. For example - increasing the value of C5 will slow it down - while reducing the value of R9 will make it faster.

While at least one switch remains closed the siren will sound. About thirty seconds after all of the switches have been opened, the alarm will reset. How long it takes to switch off depends on the characteristics of the actual components used. You can adjust the time to suit your requirements by changing the value of R6 and/or C4.

The circuit is designed to use an electronic Siren drawing 300 to 400mA. Its not usually a good idea to use the bikes own Horn because it can be easily located and disconnected. However, if you choose to use the Horn, remember that the alarm relay is too small to carry the necessary current. Connect the coil of a suitably rated relay to the "Siren" output. This can then be used to sound the Horn - flash the lights etc.

The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction. Connect the 1-amp in-line fuse AS CLOSE AS POSSIBLE to your power source. This is VERY IMPORTANT. The fuse is there to protect the wiring - not the alarm. Exactly how the system is fitted will depend on the make of your particular machine - so Im unable to provide any further help or advice in this regard.

The quiescent (standby) current of the circuit is virtually zero - so there is no drain on the battery. If you want to operate the alarm manually use a key-switch or a hidden switch connected to the "off/set" terminals. For automatic operation connect a wire from the ignition circuit to the "ignit" terminal. Then every time you turn-off the ignition - the alarm will set itself. Remember that this wire from the ignition switch is not protected by your 1-amp inline fuse. So unless its run is very short - fit the wire with its own 1-amp fuse as close as possible to its source.

When you set the alarm - if one of the switches is closed - the siren will sound. This could cause annoyance late at night. A small modification will allow you to Monitor The State Of The Switches using LEDs. When the LEDs are all off - the switches are all open - and its safe to turn the alarm on.

Veroboard Layout

 

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100W Guitar Power Amplifier Circuit Diagram

The power amp board has remained unchanged since it was first published in 2002. It definitely is not broken, so there is no reason to fix it. The picture below shows a fully assembled board (obtainable as shown as M27). Using TIP35/36C transistors, the output stage is deliberately huge overkill. This ensures reliability under the most arduous stage conditions. No amplifier can be made immune from everything, but this does come close.

Guitar Power Amplifier Board

The power amp (like the earlier version) is loosely based on the 60 Watt amp historically in the past published (Project 03), but its increased gain to match the preamp. Other modifications include the short circuit protection - the tiny groups of parts next to the bias diodes (D2 and D3). This new version is not massively different from the original, but has adjustable bias, and is designed to provide a "constant current" (i.e. high impedance) output to the speakers - this is achieved using R23 and R26. Note that with this arrangement, the gain will change depending on the load impedance, with lower impedance giving lower power amp gain. This is not a controversy, so may safely be ignored.

Ought to the output be shorted, the constant current output characteristic will provide an preliminary level of protection, but is not foolproof. The short circuit protection will limit the output current to a comparatively safe level, but a sustained short will cause the output transistors to fail if the amp is driven hard. The protection is designed not to operate under normal conditions, but will limit the peak output current to about 8.5 Amps. Under these conditions, the internal fuses (or the output transistors) will probably blow if the short is not detected in time.

Figure 2 - Power Amplifier

Figure two shows the power amp PCB parts - except for R26 which doesnt mount on the board. See Figure 1B to see where this ought to be physically mounted. The bias current is adjustable, & ought to be set for about 25mA dormant current (more on this later). The recommendation for power transistors has been changed to higher power devices. This will give improved reliability under sustained heavy usage.

As shown, the power transistors will have an simple time driving any load down to four ohms. In case you dont use the PCB (or are happy to mount power transistors off the board), you can use TO3 transistors for the output stage. MJ15003/4 transistors are high power, & will run cooler because of the TO-3 casing (lower thermal resistance). Watch out for counterfeits though! Theres plenty of other high power transistors that can be used, & the amp is tolerant of substitutes (as long as their ratings are at least equal to the devices shown). The PCB can accommodate Toshiba or Motorola 150W flat-pack power transistors with relative ease - in case you desired to go that way. TIP3055/2966 or MJE3055/2955 may even be used for light or ordinary duty.

At the input finish (as shown in Figure 1B), there is provision for an auxiliary output, & an input. The latter is switched by the jack, so you can use the "Out" & "In" connections for an outside effects unit. Alternatively, the input jack can be used to connect an outside preamp to the power amp, disconnecting the preamp.

The speaker connections permit up to 8 Ohm speaker cabinets (giving four Ohms). Do not use less than four ohm lots on this amplifier - it is not designed for it, & wont give reliable service!

All the low value (i.e. 0.1 & 0.22 ohm) resistors must be rated at 5W. The 0.22 ohm resistors will get warm, so mount them away from other parts. Needless to say, I recommend using the PCB, as this has been designed for optimum performance, and the amp gives an excellent account of itself. So nice in fact, that it may even be used as a hi-fi amp, and it sounds excellent. In case you were to make use of the amp for hi-fi, the bias current ought to be increased to 50mA. Ideally, you would use better (faster / more linear) output transistors as well, but even with those specified the amp performs well indeed. This is largely because they are run at comparatively low power, and the extreme non-linearity effects would expect with only transistors do not occur because of the parallel output stage.

Make positive that the bias transistor is attached to of the drivers (the PCB is laid out to make this simple to do). A some quantity of heat sink compound as well as a cable tie will do the job well. The diodes are there to protect the amp from catastrophic failure ought to the bias servo be incorrectly wired (or set for maximum current). All diodes ought to be 1N4001 (or 1N400? - anything in the 1N400x range is fine). A heat sink is not needed for any of the driver transistors.

The life of a guitar amp is a hard, and I recommend that you use the largest heat sink you can afford, since it is common to have elevated temperatures on stage (chiefly due to all the lighting), and this reduces the safety margin that normally applies for domestic equipment. The heat sink ought to be rated at 0.5° C/Watt to permit for worst case long term operation at up to 40°C (this is not unusual on stage).

Make sure that the speaker connectors are isolated from the chassis, to keep the integrity of the earth isolation parts in the power supply, & to make sure that the high impedance output is maintained.

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Simple Frequency to Vvoltage Converter Circuit Diagram

This is Simple Frequency to Vvoltage Converter Circuit Diagram. In these applications, a pulse input at % is differentiated by a C-R network and the negative-going edge at pin 6 causes the input comparator to trigger the timer circuit. Just as with a V-to-F converter, the average current flowing out of pin 1 is IaverAGE = i (1.1 RjC^ f. 

In this simple circuit, this current is filtered in the network RL = 100 k ohm and 1 µF. The ripple will be less than 10 mV peak, but the response will be slow, with a 0.1 second time constant, and settling of 0.7 second to 0.1%.

Simple Frequency to Vvoltage Converter Circuit Diagram

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5V 2A Dc Converter Using LT3980

Using LT3980 manufactured by Linear Technology can be designed a very simple 5 volts dc converter circuit.

5V 2A Dc Converter Circuit Diagram

The LT3980 has an adjustable frequency from 100kHz to 2.4MHz and accepts input voltages up to 58V . The transient voltage of the LT3980 is around 80 volts . The maximum output current which can be delivered by the LT3980 monolithic buck switching regulator is around 2 Amps .

Main features of the LT3980 monolithic buck switching regulator are : wide input range from 3.6V to 58V , overvoltage lockout protects circuits through 80V transients , 2A Maximum Output Current , low ripple (<15mvp-p) burst mode, aadjustable switching frequency: 100khz to 2.4mhz ,low shutdown current: iq <1μa, thermal protection, soft-start capability 

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Temperature Sensor Circuit Diagram

The LM35 temperature sensor provides an output of 10 mV/C for every degree Celsius over 0C. At 20C the output voltage is 20 10 = 200 mV. The circuit consumes 00. The load resistance should not be less than 5 kQ. A 4- to 20-V supply can be used.

Temperature Sensor Circuit Diagram

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Atv Jr Transmitter 440Mhz Circuit Diagram

This low-power video transmitter is useful for R/C applications, surveillance, or amateur radio applications. Seven transistors are used in a crystal oscillator-multiplier RF power amplifier chain, and a high-level video modulator. A 9- to 14-Vdc supply is required. Output is 0.4 to 1.2 W, depending on supply voltage. 

Atv Jr Transmitter 440Mhz Circuit Diagram

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Microcontroller Robotic Car Project by 8951

8951 Microcontroller Robotic car Project Blog diagram

Robotic Car is a miniature ancestor car powered by batteries whose assorted movements can be ascendancy either manually or automatically, or the aggregate of both. Here the command is accustomed through keyboard; it would accept been bigger if we acclimated IR alien ascendancy or article of that affectionate rather than application keyboard for commanding. However, by acumen the complexities we accept fabricated simple application keyboard.

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Circuit diagram License LGPL

Today younger brother generation that study same college comes to see at a house and beg to seek design good circuit and free. I advises a program TindyCAD because it drawing circuit diagrams commonly known as schematic drawings. It supports model the equipment is a lot of and still apply to PCB layout programs change the system netlist formats. Besides still be usable cooperate SPICE simulation netlists get as well. About the copyright be model freedom License LGPL be usable get freely model open source.

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QRO 600 VOLTS POWER SUPPLY

QRO 600 VOLTS POWER SUPPLY CIRCUIT

Amateur Radio Transmitters application valves such as 807 or1625 works able-bodied with a bowl voltage amid 600V to 700 Volts.The ambit declared actuality is a abounding beachcomber voltage doubler. The achievement voltage is alert the ascribe voltage. For 230V AC ascribe the achievement will be about 600 Volts.

Resister R1 is acclimated to absolute the antecedent aerial voltage and aerial currents. Capacitor C1, C2, C3 calm with coils L1 and L2 anatomy ascribe band filter. The capacitors C4 and C5 protects diodes from aerial voltage transients on the AC band as able-bodied as reduces inter carrier hum accentuation of the R.F best up by the mains. Capacitors C6 and C7 provides abundant clarification for the achievement DC Voltage.

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Party Like Music Produced from Acid Machine overview and explanation

Overview

This machine works by making a LED blink in the frequency of the sound and a set speed rotates the image.

Explanation

On top of the machine is the circle that contains lines where the notes being played are displayed while rotating. The lines in the middle circle will be standing still when C is played which will go outward and all notes will be displayed on a keyboard in 12 steps. The musical frequencies are displayed in centimeters for the distance between the lines. The frequencies in the circle are transformed by a script made in PHP to display the notes. To find notes using the potentiometers on the synth, the circle can also be used.

A simple noise generator and a filter comprise the sound part of the machine as it is based on logic ICs. A binary counter and a resistor ladder are used to make the 4-bit saw which is the sound the synth generates. The rotation speed of the tone wheels is determined by the red knob or the potentiometer on the controller. The notes are played as an arpeggiator by the sequencer which comes is 2 different modes.

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AM Receiver based on TDA1572 IC

The circuit is a high performance AM receiver based on the Philips TDA1572 IC. The TDA1572 is an integrated AM receiver circuit that has all the essential circuits such as RF amplifier, mixer, IF amplifier, AGC circuit, the pilot signal strength indicator, audio pre amplifier, etc. controlled oscillator incorporated into it. The internal oscillator frequency can be up to 50 Hz and the IC can accept RF signals up to 500 mV. HF inputs are static protected and separate buffer, voltage controlled oscillator makes it possible to use single coils in the circuit.

Inductor L1 connected between pins 14 and 13 of the IC sets the frequency of the oscillator. Potentiometer R12 is used to vary the voltage on the varicap tuning diode D2. C4 is associated with the internal balance of full-wave detector circuit. Pin 11 is the circuit output if the internal field indicator of strength. The power available on this pin is a function of field strength available and has a good linearity for logarithmic input signals.

The intermediate frequency of this circuit is built around 455 KHz. The band pass filter circuit ago about CF1 and CF2 6kHz select the band around the intermediate frequency. In simple words, IF double-balanced mixer output available on pin is filtered and applied to the input of gain controlled amplifier filter capacitors C16 and C17 are used to reduce the solution time of AGC. The transistor Q2 and associated components form the driver circuit M1 field strength meter. Resistors R9 R5and preset can be used to configure the meter. Capacitor C3 is a bypass capacitor for the audio preamplifier circuit of frequency within the IC. Capacitors C16 and C12 prevent noise (if any) of the power line.

TDA7052 is an audio stage 1W amplifier to drive the speaker. TDA7052 is an integrated bridge amplifier that can deliver an output power of 1W at 8 ohm speaker. Capacitor C18 couples the audio output of the TDA1572 to TDA7052. Potentiometer R10 can be used to control the volume.

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Phone Cellular Calling Detector

Phone Cellular Calling Detector

This circuit was advised to ascertain back a alarm is admission in a cellular buzz (even back the calling accent of the accessory is switched-off) by agency of a aflame LED.

The accessory charge be placed a few centimeters from the cellular phone, so its sensor braid L1 can ascertain the acreage emitted by the buzz receiver during an admission call.

The arresting detected by the sensor braid is amplified by transistor Q1 and drives the monostable ascribe pin of IC1. The ICs achievement voltage is angled by C2 & D2 in adjustment to drive the high-efficiency ultra-bright LED at a acceptable peak-voltage.

Notes:

Stand-by accepted cartoon is beneath than 200µA, accordingly a ability on/off about-face is unnecessary. Sensitivity of this ambit depends on the sensor braid type.

L1 can be fabricated by ambagious 130 to 150 turns of 0.2 mm. enameled wire on a 5 cm. bore above (e.g. a can). Remove the braid from the above and wind it with careful tape, appropriately accepting a stand-alone coil.

A bartering 10mH miniature inductor, usually awash in the anatomy of a tiny ellipsoidal artificial box, can be acclimated abundantly but with lower sensitivity.

IC1 charge be a CMos type: alone these accessories can cautiously accomplish at 1.5V accumulation or less. Any Schottky-barrier blazon diode can be acclimated in abode of the 1N5819: the BAT46 blazon is a actual acceptable choice.

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Simple Telephone Voice Amplifier Circuit

This electronic device saves the trouble of holding the telephone handset while talking. ` It is also very useful when a group of people want to listen to the telephone conversation. Under these conditions, all one has to do is to switch on the telephone amplifier and listen to the amplified voice of the caller from the speaker.
The major and the foremost advantage of the unit is that no electrical connections with the telephone are required. The telephone pickup e coil, placed close to the telephone, picks up the signal (conversation) all by itself.  Telephone pick up coil is a coil of about 3000 turns of 38 S.W.G  (Standard wire guage) copper enameled wire wound on a 2 inch diameter, plastic or paper former. The sensitivity of the unit depends upon the pickup coil and hence should be made with good care. This telephone pickup coil, when placed close to the telephone, picks up (by mutual induction) the audio frequency variations of currents produced by the telephone microphone. These signals through the coupling, are fed to the IC amplifier for amplification. The amplifier unit consists of a single IC and a few other external components.

The output signal, after amplification, is of about 400 mv in strength, This much output is sufficient to drives a small loud speaker.   After wiring the unit, connect the pickup coil to the input of the amplifier with the aid of shielded wires. Set the volume control at maximum position. Switch on the supply. Pick up  the telephone pick up coil and place it near the telephone receiver. . The amplifier unit should be placed away from the coil so as to  prevent feed back. Now lift the telephone and talk over it. At the   same time position the coil to a point where maximum output is it heard. Mark the position and fix the coil.  The current drain of the amplifier is pretty low and hence the  battery used lasts for long time. However, a battery eliminater may be used if so devised. The use of metallic cabinet or enclosures   reduces the feed back effect. 

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Active Crossover Circuit

This alive Cantankerous over is adequately beeline forward. It consists of a absorber and two 3rd order, 18 dB per octave filters. One low canyon and the added high. The cantankerous overabundance is set at 2Khz and is advised for AEK’s 400watt per access PA/Keyboard Amp systems. Obviously alone one access is apparent here.
The band akin audio arresting enters the absorber area it is astern out of phase. This is to atone for 
the filters which will alter the appearance afresh appropriately abiding the arresting to it’s able phase. The filters are more-or-less accepted low and aerial canyon filters appropriately however, added capacitors and resistors accept been added in adjustment to get the altruism bottomward to a minimum appliance alone E12 components.
This ambit may not be of awfully abundant use to anyone as it was accurately advised to clothing the applications. It is not capricious or switchable for two reasons. Firstly, it didn’t charge to be back the backdrop of the apostle arrangement were already known. And secondly, the added complication was put into the accurateness of the crossover rather than it’s flexibility. The filters are akin in account to anniversary added as able-bodied as can be accepted appliance alone E12 components. If switching were to be active to accord a ambit of abundance options, aaccommodation would accept to be fabricated on clarify accuracy.
The alone added way to accomplish a accepted crossover architecture and advance accurateness would apparently be to use Switched capacitor clarify architecture blocks. In theory, two 18or 24dB per octave filters could be complete such that they tracked anniversary added by actuality bound to the aforementioned clock. This would be a nice agreement but I haven’t had the befalling to prove this technology for this affectionate of application. My primary affair was the breach through of switching babble appliance such a design.
Therefore this architecture represents the simplest access I could booty and still get the adapted outcome.

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