Apologies if this is the wrong forum for it.
Messing around with circuits at the moment, using this PWM circuit from robotroom.com to control the position of the motor.
I've hooked up the potentiometer of the PWM to the shaft of the motor as a form of control. Turn the shaft anti clockwise, the resistance of the pot changes, causing the motor to turn clockwise until the average voltage is to low to keep it turning.
Want to add some feedback control through the form of an op amp as a differential amplifier, so that I can add a reference signal (step or ramp). So that I can cause the motor to stop at a value that isn't fully turned depending on the reference, or cause the motor to oscillate with the ramp input.
I understand how the variable pulse is generated but the top voltage rail confuses me. Not sure how the transistor works and as such don't know where the reference voltage fits in or what to take as the feedback signal.
Would it be right to replace the top rail with the output of the op amp, with the voltage output of the pot as the negative input to the op amp and the reference voltage as the positive input?
Messing around with circuits at the moment, using this PWM circuit from robotroom.com to control the position of the motor.
I've hooked up the potentiometer of the PWM to the shaft of the motor as a form of control. Turn the shaft anti clockwise, the resistance of the pot changes, causing the motor to turn clockwise until the average voltage is to low to keep it turning.
Want to add some feedback control through the form of an op amp as a differential amplifier, so that I can add a reference signal (step or ramp). So that I can cause the motor to stop at a value that isn't fully turned depending on the reference, or cause the motor to oscillate with the ramp input.
I understand how the variable pulse is generated but the top voltage rail confuses me. Not sure how the transistor works and as such don't know where the reference voltage fits in or what to take as the feedback signal.
Would it be right to replace the top rail with the output of the op amp, with the voltage output of the pot as the negative input to the op amp and the reference voltage as the positive input?