Transistor Not Gate.

Thread Starter

cjdelphi

Joined Mar 26, 2009
272
http://www.kpsec.freeuk.com/trancirc.htm

at the bottom you have a simple NOT gate using a Transistor, the trigger which is fed to base goes through a 10k resistor is this used to limit the current from the short? I've built it and it works but i'm not totally sure how it works but here's how i /think/ it works.

The trigger, goes to base, the + (positive) to the collector and the - (negative) to the emitter, not for any other reason other than to supply the (let's for argument sake an LED) as the Base voltage saturates the transistor, the current flows from Collector to Emitter (Short???).. but to me this would mean a short, so does that mean the 10k resistor or the 1k deal with the short? or am i missing something?... what happens for the duration of the short which resistor does what?

(sorry if hotlinks are not allowed I've not had time to read the rules)



http://www.kpsec.freeuk.com/images/trinvert.gif
 

thatoneguy

Joined Feb 19, 2009
6,359
When the transistor is on, the collector is connected to 0V, the current through the transistor is limited by RC. The Current through the base-emitter junction is limited by RB

When the transistor is off, no current flows through the transistor, so no voltage is dropped across RC, So the collector is at the supply voltage.

Summary: When base is high, collector is low. When base is low, collector is high.
 

PRS

Joined Aug 24, 2008
989
I believe this is just a switch that inverts the input at the output. It is therefore, logically speaking, an inverter, not a NOT gate. A gate has two or more inputs.
 

Ron H

Joined Apr 14, 2005
7,063
Thanks, SgtWookie. I almost always test my links. This is an example of Murphy's law.:D
How did you fix the link?:confused:
 
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