A Poor Man's Invertor Using Salvaged and Cheap Components

Ufff, Often there is a power cut in my residential area, don't know what to do and how to sleep at night and boom..!! Got an idea..!!!, why don't i make an invertor that atleast drives a table fan so that i could sleep peacefully at night.

And there is this invertors available in market costs around 20,000 INR. where would i get that much money to create mine... luckily there is a very familiar circuit i.e. an Astable Multivibrator or an Astable Oscillator which gives two stages of square wave output whose frequency can be manually determined...

The components needed for such a circuit would cost about 300 INR and even you can easily salvage them from old electronics, i.e., Radio, Tube light Starter, LCD display circuit, Home theatre, ETC...

Just by adding two High speed switching power MosFETs to the multivibrator we can easily PUSH and PULL voltages across a Center-tapped 12-0-12 Transformer...

This is a working circuit but has some limitations in it, because of its unregulated voltage output which is not suitable for electronic appliances i.e. TV, Mobile charger, oscilloscope, ETC.

Follow this instructables to create your's and enjoy during power cuts..!!!

Always be caution..!!! when dealing with high voltages specially when with AC...

Step 1: What Are the Components Needed...???

As mentioned Before a hand full of components is required to make the oscillator... There are two main parts in the circuit. 1) Oscillator and 2) Stepping up...

Components Required:-

a) 1K Ohms, 12K Ohms = 2 Each

b) 2.2uF 25V Electrolytic capacitor = 2Nos.

c) 2N2222 NPN small signal transistor = 2Nos. (BJT)

d) IRFZ44n NPN Power MosFET = 2Nos.

e) LED with 1K Ohm = 1 Each

f) Heat shrink tube, Radiators, Heat sink paste

g) 1000V electrical wire, Silver copper wire

h) Multimeter to check the circuit

i) 12-0-12 Transformer

j) PCB

k) Lead Acid Battery 12V

Step 2: Circuit Schematic

I created the circuit using the Online Free EasyEDA circuit, PCB creator.

Refer the image provided...

There are two stages of output obtained from T1 and T2. and there frequencies depends upon the R1, R2, R3, R4, U1, U2...

f=1.44/((R1+(2*R2))*U1

f=1.44/((R3+(2*R4))*U2

The frequencies of these two should be same to activate the MosFET and Push & Pull Voltages across the 12-0-12 side of the transformer.

This will induce a voltage difference across the 220V side of the transformer...

Step 3: Making

You will need a solder to complete the circuit in the PCB.

Before soldering in the PCB, try to create a prototype in a bread board and check the outputs of the MosFET and Transformer using Multimeter.

Based on the voltage and amp hours of the battery used as the input to the oscillator, the output timing will alter. But remember the more the voltage and amp hours the MosFET gets super hot so plan a correct radiator for it...