Phototransistor and motor feedback (4/7) - Half PWM idea скачать в хорошем качестве

Phototransistor and motor feedback (4/7) - Half PWM idea

Messing around with another idea of using an active low pass filter, to control a pnp transitor as a way to vary the output signal of a timer, giving a sort of dodgy half PWM control. First taking a look at how steep the roll-off of the active low pass filter is. Using a function generator to give the square wave test signal into the filter. With scope probes at the input and output of the filter. Then having a check of the roll-off frequency adjustment of the filter, using the potentiometer of the first timer to vary the filters clock frequency. Moving the scope probe from the filter output to the pnp transistors base resistor. To have a look at the voltage swing as the input frequency is varied over the filters roll-off. Then moving the scope probe from the transistors base over to the output of the second timer thats being used as a dodgy half PWM. First looking at the timers output while adjusting its potentiometer, used to give a change in the width of the signals low state. Then adjusting the output frequency of the function generator to see the change in the width of the signals high state.