PWM / 0-5vdc Converter

This converter circuit will convert the PWM RC Servo outputs from your interface to 0 to 5VDC signals suitable for driving air-core meters.

It uses a readily available LM324 chip. The chip contains 4 amplifiers so one chip can be used for 4 converters.  The circuit shown above should work with most interfaces but may require tweaking  since there is no common standard for PWM outputs other then the pulse varies between 1 and 2 milliseconds at about 50 Hz. 

The offset control is set for zero output when the pulse is at its minimum width.

The gain control is set for 5 VDC when the pulse is at its maximum width. PWM outputs that are faster than 50 Hz will require less gain and slower signals will require more gain. If more gain is required the 1K resistor in the gain feedback loop will have to be increased.

If you have difficulty with this circuit we will be glad to provide e-mail support.