Circuit Diagram Knowledge

The electric fence charger circuit presented here is basically a high voltage pulse generator. The super high voltage is derived from a commonly used automobile ignition coil. An a stable multivibrator is used to generate the required frequency to drive the ignition coil. Another a stable is used to control the pulses supplied to the fence.

 If you have large agricultural fields and desperately need to protect the crops from uninvited guests like animals and possibly humans, then this electric fence charger device is just what you are looking for. Build and install it yourself. An electric fence is an electrified high voltage barrier which produces painful shocks if physically touched or manipulated. Thus such fencing basically function as deterrents for animals as well as human intruders and stop them from crossing the restricted boundary.




The present circuit of an electric fence charger is designed and tested by me and has proved sufficiently powerful for the application. The circuit is able to produce voltage pulses up to 20,000 volts, needless to say about the fatality rate involved with it. However the pulses being intermittent, provides the subject with enough time to realize, recover and eject.

The generated pulse is so powerful that it can easily arc and fly-off between short distances of around a cm. so the fencing conductor needs to be separated adequately to avoid leakages through arcing and sparking. If not tackled, may drastically reduce the effectiveness of the unit.

Here the generation of high voltage is primarily carried out by an automobile ignition coil.

The winding ratios of an ignition coil are specifically designed and intended for creating high voltage arc between a two closely spaced conductors inside the ignition chamber to initiate the ignition process in vehicles.

Basically it’s just a step-up transformer, which is able to step-up an input applied voltage at its primary winding to monstrous levels at its output or the secondary winding.

SOME POINTS OF THE CIRCUIT AND THE IGNITION COIL IS VERY DANGEROUS TO TOUCH WHEN POWERED. ESPECIALLY THE IGNITION COIL OUTPUT IS TOO LETHAL AND MAY EVEN CAUSE PARALYSIS.

Let’s diagnose the whole thing more deeply.

Circuit Description

In the CIRCUIT DIAGRAMwe see that the entire circuit is basically comprised of four stages.

A DC oscillator stage, An intermediate 12 to 230 volts step-up stage, The voltage collector and firing stage and The super high voltage-booster stage.

 TR1 and TR2 are two normal step-down transformers whose secondary windings are connected through SCR2. TR2’s input primary winding may be selected as per the country specification.

IC1 along with the associated components forms a normal astable multivibrator stage. The supply voltage to the circuit is derived from the secondary of TR2 itself.

The output from the astable is used to trigger SCR2 and the whole system, at a particular fixed intermittent rate as per the settings of P1.