12V to 240V Inverter Circuit (Need Help)

[neo1]

inverter

Hi, I have a question reg this circuit, what is the use of LM358 in this circuit.
I tried to build an inverter using cd 4047 and two mosfets, got the pulse signal from 4047 but didnt get any output from mosfets, any clues plz

 

[audioguru]

Hi, I have a question reg this circuit, what is the use of LM358 in this circuit.
I tried to build an inverter using cd 4047 and two mosfets, got the pulse signal from 4047 but didnt get any output from mosfets, any clues plz

The opamps boost the low output current from the CD4047 so the circuit works better. Your circuit should have worked but with hot Mosfets.

The Mosfets have a fairly high gate-source capacitance that takes a current higher than the output of a CD4047 to charge quickly. If the Mosfets do not switch on and off quickly then they get very hot and create smoke instead of electrical power.

 

[neo1]

Thxs for ur reply audioguru
I will try to build it today and hopefully will work, few more questions reg this circuit
can I use mosfets instead of transistors ?
can I use any filter to modify square wave output or what kind of load will run on sqre wave ?

 

[audioguru]

Mosfets have a very low on-resistance so they work better than transistors in an inverter.

The 3rd harmonic of a square-wave is strong and its frequency is close to the wanted fundamental frequency.
So if you use a second-order LC filter to reduce the 3rd harmonic then the filter will also reduce the wanted fundamental frequency.

At such a low frequency the inductor in a filter will be huge and will have a high resistance which will reduce the output voltage when there is a load.

In the Philippines many people have no electricity. They use square-wave inverters to power heaters, incandescent lights, fluorescent lights and multi-voltage (90V-250V) little TVs. A business delivers a charged battery and picks up the discharged battery.