Turntable speed control

Author	Message
phil99 Guru Joined: 11/02/2018 Location: Australia Posts: 3316	Posted: 09:01pm 07 Jan 2023       Did this 40 years ago. Simple square wave inverter, 2 transistors driving the secondary of a very small 240V to 12-0-12V transformer. The capacitor value isn't critical. It still worked at 78 RPM. The new Pico PWM -Duty option would be ideal for producing the inverted and un-inverted waves for the push-pull drive , if only I could get it to work. There doesn't appear to be any inversion. "Duty cycles are specified as a percentage and you can use a negative value to invert the output (-100.0 <= duty <=100.0)." I expected this to do it. Setpin 1, PWM Setpin 2, PWM PWM 0, 67, 50, -50