/diy/ - Do It Yourself

Something happened that i haven’t been able to explain , I wrote a program to output a PWM signal, this to activate a transistors base using a PWM which I could change the frequency using a potentiometer, the program worked fine, and the circuit too, however something was happening,

1) When I lowered the frequency of my PWM the motor stopped spinning however a “buzz” could be heard from inside the motor

2) When I tried to verify my PWM signal using an oscilloscope, like in the picture, , a spark came out at the tip of the probe and the circuit stopped working, the microcontroller on my board died, (it just gets way to hot in seconds) however I still have no idea why this happened,

Hopefully someone here can explain to me what happened, I did plug my PWM signal directly to the oscilloscope before with no problems however when tried to debug in the working circuit this happened, as i recall the probe was gorunded with the circuit , but you might also want to consider the case of it not being grounded