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Old February 22, 2012, 08:09 PM
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krazyups krazyups is offline
Join Date: Mar 2008
Location: McGregor, Ontario
Posts: 274

My System Specs


Just make sure that your input signal is such that you keep the transistor in linear mode. A Tip31 has an hfe of ~100 at low currents, so to get 20mA out for your LED's you only need 200ľA of input current, so you'll need to measure the maximum output of your sound card (voltage wise) and select an appropriate resistor so that you don't exceed that.

A good project, and good ideas from the HWC community!
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