Home > Circuit Bricks > Inverter (Transistor)
UPDATED:.21:15 21 October 2013


  • When input is on, the output is off, and vice versa.
  • Also know as a NOT gate
  • Can be used to connect two different logic levels.
  • Useful if only one gate needed.
This is a useful little circuit if you need to invert a signal. For example if the output from a CONTROL goes high and you want to trigger a monostable and need a low signal, this will invert the signal.

Any general purpose low power NPN transistor should work in this circuit.


Circuit Diagram
  • Input ON = Output OFF
  • Input OFF = Output ON
Voltage Levels

Input = 0 to 0.6 volts
Output = +V (3 to 15v)

Input = 0.7 to +V volts
Output = 0 volts

Written by Phil Townshend - 2008
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