Not a problem. Those are some of the caps I mentioned in my earlier post. They are for electrical noise suppression. This doesn't happen to be a model airplane motor, does it? JohnNot sure its relevent but just to mention that the motor has 3 small unmarked caps on, 1 between legs and 1 from each leg to case.
Thanks
Great! You are almost there.I've just been checking over everything again and I've sorted the problem with the speed range. One leg of the diode from pin 7 was not soldered, I hadn't even pushed it through the board!
With that sorted the circuit works really well on the 14v supply(the battery from my cordless drill!) and the transistor stays stone cold.
Yes, probably.I don't have any large resistors, only thing I have is a 5ohm 240v AC heating element(just a coil of resistive wire), would that work?
It's a current limiter, current indicator (heat), and known load. Simple power supplies with a rectifier and capacitor (essentially what you have) are helped with a load.Also, I'm not sure what that would allow me to check?
Simple rectified AC is not "pure" like from a battery. There will be ripple from the half-waves. The capacitor and load help smooth it. Your operating PWM frequency is about 4X line frequency, so there could be some coupling effects.What do you mean by noise from the supply?
Check the AC voltage from the transformer. If it is 20 V RMS, the rectified voltage should be about 28 V.... to mains, and 2 secondary coils with 4 outputs marked 0, 20vac, 0, 20vac from left to right. I have parallelled the 2 secondary coils up and have them going into my rectifier. They output 21v