Come in and take a look.

[yongchao]

Please help me to examine this circuit.
I have made a prototype and it worked. but it died after few hours.

The idea was got from Szekeres projectin Headwize.
The Q1 suppose to be IRF 510.

Thanks.

 

[ble0t]

I believe your attempt at a DC-Servo circuit is incorrect. First, you should have the feedback going into the non-inverting input of U2. Second, the dc-servo should be connected to the inverting input of U1. Third, the feedback loop for U2 should have a resistor connected to ground and you may also want to lower the value of that capacitor. Lastly, I think you might want to put a resistor on the output of U2

Hope this helps a bit

 

[yongchao]

Thanks..
I found the problem, the lousy opamps i used for prototyping were burnt. hahaha.....
lesson learnt: never use cheap component for prototyping.

 

[av98m2]

Never use cheapo components for anything, period. Poor reliability and the added aggravation are not worth the $$$ "saved"

Its better to do one project using decent parts(by decent I don't mean uber expensive stuff btw, just affordable quality components) than many half assed ones using cheap parts that don't work very well.