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timed led.

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catcat said:
To know which pin is which, place the transistor flat side tward you with the pins facing down; in NPN or PNP the left pin will be the emitter, middle the base, and right the collector.
The European BC547 and others have the pins the exact opposite.
The Oriental 2SC945 and others have the center pin as the collector.
They are all in the same TO-92 package.
 
Ron H said:
Dunno, but we may have found who put the transistor in backwards. :)

:( oops. Thanks for ya help guys, my design has evloved a little now... i mite post a new thread for that one... ill look around a little bit first, thanks again.
 
Hey Troy...

To get back to your original question. You could use a 555 timer to control the LED headlight on your train. Basically, you would set the 555 in monostable configuration, and use input from your controller to trigger it. When you shut down the controller, a negative pulse would trigger the 555, which would then drive the headlight LED for whatever time you specify in the monostable setup (seconds, minutes, whatever). Just a suggestion.

AllVol

Edit: Ignore this suggestion. I forgot that when a 555 is triggered with a negative pulse on pin 2, the output will stay high, regardless of the rc combination, until pin two sees a positive pulse. Sorry about that.
 
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audioguru said:
The European BC547 and others have the pins the exact opposite.
The Oriental 2SC945 and others have the center pin as the collector.
They are all in the same TO-92 package.

I only have american to-92 transistors, and it works for them.
 
Everyone should save themselves the time and headaches of screwy pinouts by ALWAYS looking at the datasheet for the correct pinout.

Today, pinouts are much less standard than they use to be. Once I lookup the pinout for a part, I make a little drawing of it and keep it with my stock of parts that way, I dont have to lookup a datasheet everytime but I still always check the pinout - never guess!
 
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