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ewood
modified 9 years ago

Basic NPN as switch

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03:50:49
Using NPN Transistor as switch for turning on and off a 12v light
published 9 years ago
Robert_Kidd
9 years ago
You need a high value pull down resistor on the transistor base so it's not floating when switch is in OFF position.
ewood
9 years ago
How many ohms would you recommend?
Robert_Kidd
9 years ago
100k. Almost any value just to tie base down when switch is off. Higher value minimises current consumption.

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