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LED control via a reed switch and SCR Answered

n00b question:

I've got an RGB LED that has a forward voltage of
3.7v and a 3.7v battery pack. I want to trigger the
LED to light via a magnet and reed switch. If I wire
the reed switch to the gate of the SCR and have
the SCR power the LED, will I be able to turn the
LED on and off via the magnet by bringing the
magnet near the reed switch?



SCR's can't be turned off by turning off the trigger. Why use an SCR ? The reed switch is all you need - and a resistor to the LED

Ah, yes, that would work with the magnet remaining nearby,
but I want to latch the LED so it continues to run after taking
the magnet away. Then I want to power the LED off with the

Then you need to feed the signal from the reed-switch to a toggle-flipflop which in turn needs a supply-voltage of at least 3V or even 5V.

Ah, now that's a completely different problem, and an SCR won't help that one either !! For that, you either need a couple of relays or a small logic chip