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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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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