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Russell Bull
03/26/06 00:49
Read: 436 times

Msg Score: +1
 +1 Good Answer/Helpful
#113125 - Try using a PNP
Responding to: Bruce Grenade's previous message

If you use a PNP transistor with the emitter going to VCC, things might start to work in your favour. In this instance, the base circuit will need to fall below VCC in order for the transistor to turn on. You might wish to add a resistor between the base and the emitter(VCC) to turn the transistor off. Start with a value of around 1K at a guess.

The problem with using a NPN as per your circuit is that the base voltage would need to rise above VCC in order for it to turn on.

List of 7 messages in thread
Switching an IC off using BJT?      Bruce Grenade      03/25/06 21:36      
   Try using a PNP        Russell Bull      03/26/06 00:49      
   Good Good      Bruce Grenade      03/26/06 09:16      
      "expensive" is relative      Erik Malund      03/26/06 10:55      
         Of course      Bruce Grenade      03/26/06 11:47      
   Using a MOSFET makes sense        Kai Klaas      03/26/06 16:28      
      Good Info      Bruce Grenade      03/26/06 17:03      

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