what's going on with my LED dimmer circuit?

I'm making a resin block lighting thing for my dorm room, but the lights are too bright to look directly at (and it's meant to be looked at). I decided to make a 555 dimmer circuit, and I used these plans.


when I built it, however, the LED stayed off. I couldn't figure out what was going on until I touched the two diodes in the circuit and noticed that the small current leaking through my skin caused the LED to blink slowly. I turned one of the diodes around, and lo and behold, the dimmer worked as expected.

so what I want to know is:

what was the purpose of the diodes in the original diagram?
was the positioning of the diodes just an error in the design?
should I run with what I have now (since it works), or do something different?

The original circuit is WRONG, the diodes should be in opposite ways round. One path charges the capacitor through one section of the pot, the other path discharges the cap through the chip. Stay with what you have.
codongolev (author)  steveastrouk3 years ago
thank you. I figured, but since the whole circuit is going to be embedded in epoxy I figured I should double check.