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Author Topic: Unusual Transistor Circuit  (Read 1378 times)

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thgreer

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Unusual Transistor Circuit
« on: October 31, 2013, 00:28:48 AM »
Has anyone every seen a transistor amplifier circuit which uses the collector as the input? The circuit is part of an IR remote control transmitter I am modifying to control something else. I have triple-checked the existing circuit (see attached). I am familiar with common emiiter, common base, and common collector circuits, but this is something new to me.

kam

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Re: Unusual Transistor Circuit
« Reply #1 on: October 31, 2013, 01:20:01 AM »
The base-emitter diode is forward biased, so i can only see a diode there and nothing else. When the input IN becomes higher than the 3V of the LED, then the LED is reverse biased and most likely it will turn off. You can simply remove the transistor and connect everything in one node or better replace it with 2 diodes... Funny connection.