I have gathered the components for a PWM circuit found at this website

http://www.alt-nrg.org/

I am planning on building the Constant Current Version 2 schematic.

I would like to experiment on injecting different things into my engine for increased mileage, and needed an easy way to control the PWM output from 10% to 100% via a 1-4.5 VDC signal from my Throttle Possition Sensor( I looked up the voltage output from my repair manual). Is this possible to do in a simple way?

 

Use a comparator IC, feed its inverting input with a triangular wave and on the non-inverting apply the varying DC voltage. As you increase the DC voltage the duty cycle will increase.

 

Mik3,

Thanks for the reply. Sorry it took so long to get back. I do not exactly know how to implement the comparator IC into this particular circuit. Can you point me in the corect direction here? Thanks again,

Josh

 

Have a look here:

http://www.solorb.com/elect/solarcirc/pwm1/