Current flow through NPN transistor to resistor.

Thread Starter

benphillips

Joined Mar 29, 2019
9
I have a question about this circuit.




Since electrons flow from negative to positive.
When the points are open, is a there current flowing through the emitter, through the base, to the R1 resistor?

If so, when the points close, does current stop flowing from emitter to base?
 

Thread Starter

benphillips

Joined Mar 29, 2019
9
Thank you. I don't know why I mentioned the electron flow.

If I unplug the collector from the G Terminal, connect a meter from battery postive to the collector, will I have 0V when the points are closed? and have voltage when the points are open?
 

Ylli

Joined Nov 13, 2015
850
If I unplug the collector from the G Terminal, connect a meter from battery postive to the collector, will I have 0V when the points are closed? and have voltage when the points are open?
Yes, the transistor will be off when the points are closed, and on when the points are open. When the transistor is on, you will see almost the full battery voltage between the + rail and the collector. With the transistor off, you would see zero on the voltmeter if the transistor was perfect - but in reality they have a bit of leakage. So you will see *near* zero.
 

crutschow

Joined Mar 14, 2008
23,741
If I unplug the collector from the G Terminal, connect a meter from battery postive to the collector, will I have 0V when the points are closed? and have voltage when the points are open?
Yes, again.
But there may be a small voltage when the points are closed due to leakage current in the transistor.
 
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