GeekDoc 226 Posted September 22, 2010 Share Posted September 22, 2010 When I wanted a more sensitive IR sensor for my project, I (basically) tied the emitters and collectors of two IR phototransistors together. The bases were effectively tied, since they were both pointed at the same IR source. This brings my question: If you tie all the leads of two NPN transistors together, could you effectively amplify a voltage, even though the transistors are in a "voltage following" configuration? i.e.: collectors tied to 3v, emitters tied to an MSP430 i/o pin, bases tied together. Apply 1.5v to base. Can you get close to 3v at i/o pin? I've been wondering because I've been trying to figure out a minimal-parts solution to gatesphere's PIR sensor problem (only gets 1.7v signal when run off 3v; not enough to trigger MSP430, especially with pull-down resistor). If I had a little more time, I'd try this out myself, but I thought someone might know. Quote Link to post Share on other sites
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