Laser ON/OFF switch using NPN transistor

Created by	aweijnitz
Created	January 20, 2013
Last modified	January 20, 2013
Tags	arduino laser npn-transistor

How to hookup a laser module to an Arduino, using an NPN transistor to control it.

Calculation, based on 20mA typical operating current draw from the laser module.

Ic = 20mA = 0.020A
Ib = Ic/10 = 0.002A
Rb = Vs/Ib = 5/0.002 = 2500 Ohm

Laser module I used:
http://www.seeedstudio.com/depot/5mw-laser-module-emitter-red-point-p-72.html?cPath=156_161

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Thx for the info. Did you used the arduino 5 volt or an external power source?

by Geyst
February 27, 2013

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Laser ON/OFF switch using NPN transistor PUBLIC