Booster Low Power Voltage Doubler Diagram Circuit

All miniature electronic devices operate off batteries. Some of them need higher than the standard battery voltages to operate efficiently. If the battery of that specific voltage is unavailable, we are forced to connect additional cells in series to step up the DC voltage. Thus, the true meaning of miniaturisation is lost. A simple way to overcome this problem is to employ a voltage doubler, if the device under consideration can operate at a small current.

Here we present a low-power voltage doubler circuit that can be readily used with devices that demand higher voltage than that of a standard battery but low operating current to work with. The circuit is quite simple as it uses only a few components. Yet, the output efficiency is 75 to 85 percent along its operating voltage range. The available battery voltage is almost doubled at the output of the circuit.

Here IC1 is wired as an astable multivibrator to generate rectangular pulses at around 10 kHz. This frequency and duty cycle of the pulses can be varied using preset VR1. The pulses are applied to switching transistors T1 and T2 for driving the output section, which is configured as a voltage-doubling circuit. The doubled voltage is available across capacitor C5. During each cycle of the pulse occurance, the high level drives T1 into its saturation, keeping transistor T2 cut off.Circuit diagram:

Low-Power Voltage Doubler Circuit Diagram

So transistor T1 charges capacitor C4 via the path formed by diodes D2 and D1 to a voltage level slightly lesser than the supply. But during the low period of the pulse, transistor T1 is cut off while transistor T2 is driven into saturation. Now, transistor T2 raises the charge on the negative pole of capacitor C4 by another step equal to the supply voltage. Therefore an equal amount of charging is built up on capacitor C5 via diode D3.

This doubling action increases the total voltage across capacitor C5 to almost double the input voltage. If the output of the pulse generator is maintained with a high enough amplitude and frequency, the output voltage and current remain constant and cater to the needs of the load. Even with the half-wave function, this circuit is almost free of ripple voltage. If the connected load doesn’t require a high current, the efficiency can be expected in the upper 90 percentranges.

Since the input voltage is doubled, the current drain from the input power supply is also doubled at the input but halved at the output. One point of caution is that if the multivibrator’s frequency is fairly high, the output may suffer with the interference imposed over the DC voltage. In this case, the frequency must be set favorably by trials and actual load connection procedure. This tiny circuit can be assembled on the general-purpose PCB. If all of the components are surface-mount type, the whole module can be genuinely miniaturized.EFY Lab note.
During testing with input of 8V and 1.25mA load current the output voltage was found to be around 13V.
Source: EFY Mag

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Voltage Controlled Oscillator

In most cases, the frequency of an oscillator is determined by the time constant RC. However, in cases or applications such as FM, tone generators, and frequency-shift keying (FSK), the frequency is to be controlled by means of an input voltage, called the control voltage. This can be achieved in a voltage-controlled oscillator (VCO). A VCO is a circuit that provides an oscillating output signal (typically of square-wave or triangular waveform) whose frequency can be adjusted over a range by a dc voltage.

Voltage Controlled Oscillator Block Diagram :

An example of a VCO is the 566 IC unit, that provides simultaneously the square-wave and triangular-wave outputs as a function of input voltage. The frequency of oscillation is set by an external resistor R1 and a capacitor C1 and the voltage Vc applied to the control terminals. Figure shows that the 566 IC unit contains current sources to charge and discharge an external capacitor Cv at a rate set by an external resistor R1 and the modulating dc input voltage.

A Schmitt trigger circuit is employed to switch the current sources between charging and discharging the capacitor, and the triangular voltage produced across the capacitor and square-wave from the Schmitt trigger are provided as outputs through buffer amplifiers. Both the output waveforms are buffered so that the output impedance of each is 50 f2. The typical magnitude of the triangular wave and the square wave are 2.4 Vpeak.to-peak and 5.4Vpeak.to.peak.

The frequency of the output waveforms is approximated by : fout = 2(V+ - Vc)/R1C1V+

Voltage Controlled Oscillator Circuit Diagram :

Figure shows the pin connection of the 566 unit. The VCO can be programmed over a 10-to-l frequency range by proper selection of an external resistor and capacitor, and then modulated over a 10-to-l frequency range by a control voltage, Vc The voltage controlled oscillators (VCOs) are commonly used in converting low-frequency signals such as EEG (electro-encephalograms) or ECG (electro-cardiograms) into an audio­frequency (AF range).

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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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Over Voltage Protector Wiring diagram Schematic

This schema protects your television as well as other electrical appliances from over-voltage. It uses operational amplifier µA741 (IC1) as a comparator. The unregulated power supply is connected to resistor R3 and preset VR1 through resistor R2. Zener diode ZD1 provides reference voltage of 5.1V to the inverting input (pin 2) of IC1.

 Over-Voltage Protector Circuit Diagram

The non-inverting input (pin 3) of IC1 senses voltage fluctuation in the mains. Preset VR1 is adjusted such that for mains supply below 240V AC, the voltage at the non-inverting terminal of IC1 is less than 5.1V. Hence the output of IC1 is zero and transistor T1 is in non-conducting state. At the same time transistor T2 conducts to energise relay RL1 to connect the mains to the load.

When AC mains is beyond 240V, the voltage at pin 3 of IC1 goes above 5.1V. The high output of IC1 drives transistor T1 and transistor T2 stops conducting to de-energise the relay. Hence the appliance turns off.

Preset VR2 is used for proper biasing of transistor T1. The AC mains supply is stepped down by transformer X1 to deliver a secondary output of 7.5V-0-7.5V AC, 1A. The output of the transformer is rectified by a full-wave rectifier comprising diodes D1 through D4. Capacitors C1 and C2 act as filters to eliminate ripples. Regulator IC 7812 is used to provide regulated 12V supply.

Sourced: EFY : Author P.V. Vinod Kumar

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Under voltage Indicator for Battery Equipment Wiring diagram Schematic

This is the simple Under voltage Indicator for Battery Equipment Circuit Diagram. Due to the low duty cycle of flashing LED, the average current drain is 1 mA or less. The NE555 will trigger the LED on when the monitored voltage falls to 12 volts.The ratio of Rl to R2 only needs to he changed if it is desired to change the voltage point at which the LED is triggered.

Under voltage Indicator for Battery Equipment Circuit Diagram

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Voltage Regulator with Shutdown Digital Wiring diagram Schematic

This Voltage Regulator with Shutdown Digital Circuit Diagram is very interesting, it uses an LM317 regulator schema that allows external control in a dangerous situation to turn off the regulator output in response to the trigger. The schema is configured to output five volts suitable for all TTL logic diagram. The selected values ​​of R1 and R2 set the output to the required 5V, R2 can be changed to other values ​​other output voltages.

In unfavorable external trigger switches the transistor instantly putting R2 shorted to ground, knocking the output to zero volts.As the schema is equipped with the function off by an external trigger, it is extremely suitable for many critical applications and for use in Arduino projects.

Voltage Regulator with Shutdown Digital Circuit Diagram

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Power Supply Voltage Indicator Circuit

Power Supply Voltage Indicator Circuit

Notes

This simple and hardly odd ambit can acutely appearance the akin of the accumulation voltage (in a beyond device): as continued as the indicator has acceptable 12 volts at its input, LED1 gives steady, ceaseless (for the naked eye) chicken light. If the ascribe voltage avalanche beneath 11 V, LED1 will alpha to blink and the blinking will aloof get slower and slower if the voltage drops added - giving actual bright and automatic representation of the supplys status. The blinking will stop and LED1 will assuredly go out at a little beneath 9 volts.

On the added hand, if the ascribe voltage rises to 13 V, LED2 will alpha to glow, accepting at about abounding ability at 14 V.

The appropriate voltages can be adapted primarily by adjusting the ethics of R1 and R4.

The base-emitter diode of T2 basically aloof stands in for a zener diode. The emitter-collector aisle of T1 is inversely polarized and if the ascribe voltage is aerial abundant - T1 will account oscillations and the abundance will be proportional to the ascribe voltage. The alleviation oscillator ceases cycling back the ascribe voltage gets so low that it no best can account breakdown forth the emitter-collector path.

Not all baby NPN transistors appearance this affectionate of behavior back inversely polarized in a agnate manner, but abounding do. BC337-40 can alpha oscillations at a almost low voltage, added types about crave a volt or two more. If experimenting, be accurate not to bite a aperture through the accessory beneath test: they oscillate at 9-12 V or not at all.

via : http://www.zen22142.zen.co.uk

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Build a Car Voltage Regulator Circuit Using LM317

The car cigarette lighter socket does not only light cigarettes, but can be utilized as an electrical channel for powering tools to work on the car such as laptops and other electronic devices. The following schema diagram shows a way of powering a two-way mobile radio using the LM317T voltage regulator.

The LM317T is an adjustable 3-terminal positive voltage regulator that efficiently provides a load current of 1.5 Amps over an output range of 1.2 V and 37 V. With reference to the schema, it can accept 14 volts without any hassle and the voltage can be controlled easily with the use of a potentiometer, a 3-terminal resister with sliding contact. The whole schema will contain the following components:

 Printed Circuit Board (PCB)
Resistor 1 (R1): 270 ohms
Resistor 2 (R2): 2K carbon potentiometer
Capacitor 1 (C1): 100nF
Capacitor 2 (C2): 1uF tantalum
LM317T Voltage Regulator
Heat Sink
DC Power Jacks
Green LED: Power
Red LED: Over Voltage
Zener Diode: over voltage LED switch

The zener diode switches on the over voltage LED if the voltage passing through is larger than the breakdown or preset voltage. The use of zener diode permits a constant amount of voltage and can be very beneficial for devices that inputs the same amount of voltage.

LM317T is cheaply available in the market and is very simple to integrate into several energy system to supply a maximum current or voltage.

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How to Build a Photodiode current to voltage converter

The Photodiode current-to-voltage converter schema uses three CA3130 BiMOS op amps in an application sensitive to sub-picoampere input currents. The schema provides a ground-referenced output voltage proportional to input current flowing through the photo-diode.

 Photodiode current-to-voltage converter schema

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Mini High Voltage Generator Circuit

Mini High-Voltage Generator Circuit. Here’s a project that could be useful this summer on the beach, to stop anyone touching your things left on your beach towel while you’ve gone swimming; you might equally well use it at the office or workshop when you go back to work. In a very small space, and powered by simple primary cells or rechargeable batteries, the proposed schema generates a low-energy, high voltage of the order of around 200 to 400 V, harmless to humans, of course, but still able to give a quite nasty ‘poke’ to anyone who touches it.

Quite apart from this practical aspect, this project will also prove instructional for younger hobbyists, enabling them to discover a schema that all the ‘oldies’ who’ve worked in radio, and having enjoyed valve technology in particular, are bound to be familiar with. As the schema diagram shows, the project is extremely simple, as it contains only a single active element, and then it’s only a fairly ordinary transistor. As shown here, it operates as a low-frequency oscillator, making it possible to convert the battery’s DC voltage into an AC voltage that can be stepped up via the transformer.

Using a centre-tapped transformer as here makes it possible to build a ‘Hartley’ oscillator around transistor T1, which as we have indicated above was used a great deal in radio in that distant era when valves reigned supreme and these was no sign of silicon taking over and turning most electronics into ‘solid state’. The ‘Hartley’ is one of a number of L-C oscillator designs that made it to eternal fame and was named after its invertor, Ralph V.L Hartley (1888-1970). For such an oscillator to work and produce a proper sinewave output, the position of the intermediate tap on the winding used had to be carefully chosen to ensure the proper step-down (voltage reduction) ratio.

Here the step-down is obtained inductively. Here, optimum inductive tapping is not possible since we are using a standard, off-the-shelf transformer. However we’re in luck — as its position in the centre of the winding creates too much feedback, it ensures that the oscillator will always start reliably. However, the excess feedback means that it doesn’t generate sinewaves; indeed, far from it. But that’s not important for this sort of application, and the transformer copes very well with it.

The output voltage may be used directly, via the two current-limiting resistors R2 an R3, which must not under any circum-stances be omitted or modified, as they are what make the schema safe. You will then get around 200 V peak-to-peak, which is already quite unpleasant to touch. But you can also use a voltage doubler, shown at the bottom right of the figure, which will then produce around 300 V, even more unpleasant to touch. Here too of course, the resistors, now know as R4 and R5, must always be present. The schema only consumes around a few tens of mA, regardless of whether it is ‘warding off’ someone or not! If you have to use it for long periods, we would however recommend powering it from AAA size Ni-MH batteries in groups of ten in a suitable holder, in order not to ruin you buying dry batteries.

Mini High-Voltage Generator Circuit Circuit diagram:

Warning!
If you build the version without the voltage doubler and measure the output voltage with your multimeter, you’ll see a lower value than stated. This is due to the fact that the waveform is a long way from being a sinewave, and multimeters have trouble interpreting its RMS (root-mean-square) value. However, if you have access to an oscilloscope capable of handling a few hundred volts on its input, you’ll be able to see the true values as stated. If you’re still not convinced, all you need do is touch the output terminals...

To use this project to protect the handle of your beach bag or your attachecase, for example, all you need do is fix to this two small metallic areas, quite close together, each connected to one output terminal of the schema. Arrange them in such a way that unwanted hands are bound to touch both of them together; the result is guaranteed! Just take care to avoid getting caught in your own trap when you take your bag to turn the schema off!

Copyright : Elektor Electronics 2008

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Over voltage Protection Wiring diagram Schematic

This is a Over voltage Protection Circuit Diagram. A silicon-controlled rectifier is installed in parallel with the 12-V line and connected to a normally-closed 12-V relay, K1. The SCRs gate schema is used to sample the applied voltage. As long as the applied voltage stays below a given value, SCR1 remains off and Kls contacts remain closed, thereby supplying power to the load. 

When the source voltage rises above 12 V, sufficient current is applied to the gate of SCR1 to trigger it into conduction. The trigger point of SCR1 is dependent on the setting of R1. Once SCR1 is triggered (activating the relay), K1s contacts open, halting current flow to the load.

Over voltage Protection Circuit Diagram

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Simple Period To Voltage Converter Wiring diagram Schematic

This is a Simple Period-To-Voltage Converter Circuit Diagram. The schema input signal drives ICD. Because ICD`s positive input (V+) is slightly offset to + 0.1 V, its steady state output will be around +13 V. This voltage is sent to ICC through D2, setting ICC`s output to +13 V. Therefore, point D is cut off by Dl, and CI is charged by the current source. 

Assuming the initial voltage on CI is zero, the maximum voltage (^Cinax) is given by: When the input goes from low to high, a narrow positive pulse is generated at point A. This pulse becomes -13 V at point B, which cuts off D2. ICC`s V+ voltage becomes zero. The charge on CI will be absorbed by ICC on in a short time. 

The time constant of C2 and R5 determines the discharge period— about 10 /is. ICB is a buffer whose gain is equal to (R& + R9)~Rg = lM5. ICD`s average voltage will be (1362f 1.545) + 2 = 1052/. RIO and C3 smooth the sawtooth waveform to a dc output.

Simple Period-To-Voltage Converter Circuit Diagram

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Build A Voltage Inverter using IC NE 555

In many diagram we need to generate an internal adjustable voltage. This schema shows how it is possible to use a trusty old NE555 timer IC and a bit of external schemary to create a voltage inverter and doubler. The input voltage to be doubled is fed in at connector K1. To generate the stepped-up output at connector K2 the timer IC drives a two-stage inverting charge pump schema.

The NE555 is configured as an astable multivibrator and produces a rectangular wave at its output, with variable mark-space ratio and variable frequency. This results in timing capacitor C3 (see schema diagram) being alternately charged and discharged; the voltage at pin 2 (THR) of the NE555 swings between one-third of the supply voltage and two-thirds of the supply voltage.

Voltage Inverter Circuit Using IC NE555

The output of the NE555 is connected to two voltage inverters. The first inverter comprises C1, C2, D1 and D2. These components convert the rectangular wave signal into a nega-tive DC level at the upper pin of K2. The second inverter, comprising C4, C5, D3 and D4, is also driven from the output of IC1, but uses the negative output voltage present on diode D3 as its reference potential. The consequence is that at the lower pin of output connector K2 we obtain a negative volt-age double that on the upper pin.

Now let us look at the voltage feedback arrangement, which lets us adjust this doubled negative output voltage down to the level we want. The NE555 has a control voltage input on pin 5 (CV). Normally the voltage level on this pin is maintained at two-thirds of the supply voltage by internal schemary. The voltage provides a reference for one of the comparators inside the device. If the reference voltage on the CV pin is raised towards the supply voltage by an external schema, the timing capacitor C3 in the astable multivibrator will take longer to charge and to discharge. As a result the frequency of the rectangle wave output from IC1 will fall, and its mark-space ratio will also fall.

The source for the CV reference voltage in this schema is the base-emitter junction of PNP transistor T1. If the base volt-age of T1 is approximately 500 mV lower than its emitter voltage, T1 will start to conduct and thus pull the voltage on the CV pin towards the positive supply.

In the feedback path NPN transistor T2 has the function of a voltage level shifter, being wired in common-base configuration. The threshold is set by the resistance of the feedback chain comprising resistor R3 and potentiometer P1. When the emitter voltage of transistor T2 is more than approximately 500 mV lower than its base voltage it will start to conduct. Its collector then acts as a current sink. Potentiometer P1 can be used to adjust the sensitivity of the negative feedback schema and hence the final output voltage level.Using T1 as a voltage reference means that the schema will adjust itself to compensate not only for changes in load at K2, but also for changes in the input supply voltage. If K2 is disconnected from the load the desired output voltage will be maintained, with the oscillation frequency falling to around 150 Hz.

A particular feature of this schema is the somewhat unconventional way that the NE555’s discharge pin (pin 7) is connected to its output (pin 3). To understand how this trick works we need to inspect the innards of the IC. Both pins are outputs, driven by internal transistors with bases both connected (via separate base resistors) to the emitter of a further transistor. The collectors of the output transistors are thus isolated from one another [1].

The external wiring connecting pins 3 and 7 together means that the two transistors are operating in parallel: this roughly doubles the current that can be switched to ground.The two oscilloscope traces show how the output voltage behaves under different circumstances. The left-hand figure shows the behaviour of the schema with an input voltage of 9 V and a resistive load of 470 Ω connected to the lower pin of output connector K2. The figure on the right shows the situation with an input voltage of 10 V and a load of 1 kΩ on the lower pin of output connector K2. The pulse width and frequency of the rectangle wave at the output of IC1 are automatically adjusted to compensate for the differing conditions by the feedback mechanism built around T1 and T2.

Because of the voltage drops across the Darlington out-put stage in the IC (2.5 V maximum) and the four diodes (700 mV each) the schema achieves an efficiency at full load (470 Ω between the output and ground) of approximately 50 %; at lower loads (1 kΩ) the efficiency is about 65 %. Link

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Build a Efficient Negative Voltage Regulator Wiring diagram Schematic

How to Build a Efficient Negative Voltage Regulator Circuit Diagram. This simple Efficient Negative Voltage Regulator Circuit Diagram is One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode schema transformer. The technique works with any positive-voltage regulator, although highest efficiency occurs with low-dropout types. 

Under all loading conditions, the minimum voltage difference between the regulator ViN and VoUT pins must be at least 1.5 V, the LT1086`s low-dropout voltage. Efficient-negative-voltage-regulator Rating: 7.00/10 (23Votes cast)Category: Power Supply Circuits / AC to DC & DC to DCViews: 3Rank: 5One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode schema transformer. 

 Efficient Negative Voltage Regulator Circuit Diagram

The technique works with any positive-voltage regulator, although highest efficiency occurs with low-dropout types. Under all loading conditions, the minimum voltage difference between the regulator ViN and VoUT pins must be at least 1.5 V, the LT1086`s low-dropout voltage.Efficient-negative-voltage-regulatorIf this requirement isn`t met, the output falls out of regulation. 1vo programming resistors, R1 and R2, set the output voltage to 12 V, and the LT1086`s servo the voltage between the output and its adjusting (ADJ) terminals to 1.25 V. 

Capacitor C1 improves ripple rejection, and protection diode D1 eliminates common-load problems. Since a secondary winding is galvanically isolated, a regulator`s 12 V output can be referenced to ground. Therefore, in the case of a negative-voltage output, the positive-voltage terminal of the regulator connects to ground, and the -12 V output comes off the anode of Dl. The ViN terminal floats at 1.5 V or more above ground.

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Low Voltage Amplifier Circuit with IC BA518

This Circuit use IC BA518 or you can use the IC BA547 , this is low mono power amplifier. Maximum power output 5W . But this is also low voltage amplifier with minimum voltage require 2 Volt. And maximum voltage 12 Volt .Impedance 8 Ohm , support small speakers.

Circuit schematic below :

Click image to view large

Troubleshooting if circuit not working  :

• Check components are can be use or not , also check the use avometer or other measuring instrument. 

• Check the voltage on each component. 

•  If there is a voltage that has not been entered on the components, then see if there is a broken line or short-circuit PCB , thereb inhibiting the incoming flow.

• Then check  whether the input and output cables are still good or not.

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Voltage to frequency converters LM231 LM331

The LM231/LM331 family of voltage-to-frequency converters are ideally suited for use in simple low-cost circuits for analog-to-digital conversion, precision frequency-to-voltage conversion, long-term integration, linear frequency modulation or demodulation, and many other functions

Voltage-to-frequency converters LM231/LM331

Features Voltage-to-frequency converters LM231/LM331:

- Guaranteed linearity 0.01% max
- Improved performance in existing voltage-to-frequency
conversion applications
- Split or single supply operation
- Operates on single 5V supply
- Pulse output compatible with all logic forms
- Excellent temperature stability, ±50 ppm/°C max
- Low power dissipation, 15 mW typical at 5V
- Wide dynamic range, 100 dB min at 10 kHz full scale
- Wide range of full scale frequency, 1 Hz to 100 kHz
- Low cost

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Simple Source Voltage Protector

Protection of electronic devices with a DC voltage source of voltage source obligatory reversal, especially protection of the source voltage is reversed. The definition of "Protectors Voltage Sources" in this article are the source voltage surge protector circuit which serves to protect the device from the reversal of the voltage source to the appliance electronics.

Source voltage surge protector will expressed in this article are general, so that later in their applications to stay adjusted value of the component with the voltage source needs an electronic appliance. Let us start reviewing Protectors Voltage Source by simple and modest.

Source voltage protection with 1 diode

Diodes are used as a protector of the source voltage installation tebaliknya voltage source is installed in series with the input line voltage source electronics devices. Installation of surge protector diode as a voltage source is on the positive line voltage source input device. The function is to drain diode current (voltage source) in one direction only, so that in the event of an upside-down voltage source. then the voltage source is not in the channel (in blocks) to the device. The value of the diode is tailored to the needs of the source voltage of the device itself.

Source voltage protection with dioda bridge

Protectors voltage source with a diode bridge in principle the same as the surge protector with a voltage source diode 1 pc. The difference is the source voltage surge protector is not blocking the source voltage, but the source voltage surge protector is to reverse the flow of the source voltage of one polarity in the case of voltage source. From the picture above to explain the purpose of reversing the voltage source in question, namely when given a source voltage through a voltage surge protector is the source of positive polarity (+) will be directly in the stream leading to the positive input line of tools and the source of negative voltage (-) will be directed to the negative voltage source input line tool.

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Voltage regulator with LT1086

One way to provide good negative-voltage regulation is with a low-drop-out positive-voltage regulator operating from a well-isolated secondary winding of a switch-mode circuit transformer. The technique works with low-dropout types.

Under all loading conditions , the minimum voltage difference between the regulator Vin and Vout pins must be at least 1.5V , IC LT1086 low-dropout voltage. If this requirement isnt met, the output falls out of regulation. Two programming resistors, R1 and R2, set the output voltage 12V, and the IC LT1086 servo the voltage between the output and its adjusting terminals to 1.25V. Capacitor C1 improves ripple rejection, and protection diode D1 eliminates common-load problems.

Since a secondary winding is galvanically isolated , a regulator 12V output  can be referenced to ground. Therefore , in the case of a negative-voltage output , the positive-voltage terminal of the regulator connects to ground , and the 12V output comes off the anode of D1. The Vin terminal floats at 1.5V ore above ground.

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