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| General Electronics Chat This forum is for general chat about electronics, eg: Dont know what a part does? Dont know how to read a circuit? Want to get an opinion? |
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29th July 2004, 10:54 AM
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 Identify function of a diode Hi, I made a PIC programmer (Velleman kit) but I am having some stability problems with the device. LED's which are powered by the main 5v bus aren't lighting when switched, so I'm trying to find a cause... My question is... what is the Diode D7's function in this circuit? Is it to stop negative going pulses from reaching T4? The input through R13 is direct to a serial cable, pins 9 AND 3. | |
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29th July 2004, 12:39 PM
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| Yes, it's to stop negative signals to reach the transistor... a serial port outputs a positive voltage for a logic 1 and a negative voltage for a logic 0. The diode will short out the negative signals | |
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29th July 2004, 01:27 PM
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| Great, thanks... discussion has moved to the following message now: http://www.electro-tech-online.com/v...?p=52336#52336 | |
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Linear Mode
