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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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1st January 2008, 10:46 PM
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 IR Transmitter Circuit Hi All, I have been looking at Nigel Goodwin's PIC tutorial, particularly the infrared circuit. I have attached the circuit but removed the receiver element as I am particularly interested in the TX. I understand what it all does except for the reason for why R4 is brought to GND, a potential divider? why couldnt R3 and R4 be in series with the base of the transistor? Thanks Mark | |
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1st January 2008, 10:59 PM
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| Aha! let me try and answer my own question, is this a "pull-down" resistor? Mark | |
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2nd January 2008, 01:07 AM
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| Yes! It helps turn the transistor off, by discharging the base charge. | |
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