Changing A Light Source

Dr. Lettsome,

Thank you so much for your video. I learnt a lot form it.

Do you think a light from a red LED can activate your switch in your video “Light Sensitive Switch“?

Or what kind of photo-diode do you think can do that job, i.e. activate a switch by a light emitted by a single small red LED?

Many thanks!

Clyde A. Lettsome, PhD, PE, MEM Answer: The circuit will work with a red LED placed within a reasonable proximity of the photo-diode. You may need to adjust the potentiometer in the circuit to drop the reference (threshold) voltage. By doing so, the circuit becomes more sensitive to light.

Good Luck!

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