Protect Your Home Appliances By Building This Simple Automatic Voltage Stabilizer

There are huge varieties of voltage stabilizers available in the market, and surely it's not a big deal to procure one, according to the needs. But off course it can be very amusing to build one at home all by you and see it actually working. The circuit of an Automatic Voltage Stabilizer (AVS) described in this article is in fact very simple in design, reasonably precise and will give a good protection to the electronic gadget that is connected to it. It will particularly guard them against the dangerous high voltages and also from the possible brownouts (low voltages).The output will stay in the range of 200VAC – 255VAC with an input voltage of 175VAC – 280VAC.

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The circuit of a voltage stabilizer basically consists of a voltage sensor. It is configured to detect the rise or fall of the AC mains voltage to dangerous levels. As soon it senses a risky input voltage, it immediately energizes the relays connected to it. These relays in turn swaps and switches the appropriate winding terminals of the auto transformer to correct and stabilize the output voltage. Thus the appliance which is connected to the output of the voltage stabilizer circuit always receives a safe, tolerable voltage and is able to function reliably, irrespective of the fluctuating input voltages.

Let’s proceed to know what are the parts required to build it and also its construction details.

You will require the following parts for the circuit:

• Resistor ¼ watt, CFR R1 = 2 K 7,

• Preset P1 = 10 K Linear,

• Transistor T1 = BC 547,

• Zener diode Z1 = 3 V / 400 mW,

• Diode D1, D2 = 1N4007,

• Capacitor = 220uF / 25 V

• Relay RL1 = 12 V / DPDT mini (double pole, double throw),

• Transformer T1 = 12 – 0 – 12 V / 5 amps. T2 = 0 – 12 volts / 500 mA (input as per country specifications)

• General purpose board = 3” by 3”

With the help of the given circuit schematic (on the next page) the construction of this simple AVS circuit may be completed through the following easy steps:

• In the given piece of general purpose board, insert the transistor, solder and cut its leads.

• Proceed by fixing and soldering the rest of the associated parts along with the relay around the transistor.

• Interlink all of them as per the circuit schematic.

• Finally connect the primary and the secondary wires of the transformer to the relay contacts as shown in the diagram.

The next page covers the circuit and the construction details of this automatic voltage stabilizer circuit.