help me design a PWM circuit
I am gonig to try and make a project which will mix the light from R,G, and B leds as a color mixing experiment. I would like to drive each led with a constant voltage but pulse them to achieve a variable brightness. I want the bass frequency to be 30 pulses per second and the width to vary from zero to 1/30 second. I would like for it to be controlled by a knob and to have a meter which will read pulse width or maybe even intensity. Or it could just read pulse width and I could devise a formula to relate the two.
I think a 555 timer could provide the 30 pulses per second, and have a RC circuit to adjust the pulse width. The voltage from the cap could go to a transistor which would act like a switch switching whatever voltage i select for the LED.
help me from here!
Thanks!
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