Electronically programmable inverter
- a simple circuit enabling an invert / non-invert function to be
switched using an exclusive OR gate
This electronic circuit is a particularly elegant for its
simplicity. Using a single NOR gate it provides the ability to either invert or
not invert a logic signal.
Simply using the truth table for the exclusive OR function it
can be seen that when there is a low on one input to the exclusive OR gate, the
signal on the other input is passed through the circuit and not inverted. When
the signal on one input is a high, then the signal on the other is inverted at
the output.
Exclusive OR truth table
A |
B |
Output |
0 |
0 |
0 |
0 |
1 |
1 |
1 |
0 |
1 |
1 |
1 |
0 |
As seen from the electronic circuit below, it consists of an
exclusive OR gate, a pull up resistor and a switch. The control line could come
from an external source such as another gate. In this case there would be no
need for the pull up resistor, and the circuit would simply consist of the
single gate held within the integrated circuit.
![Programmable Inverter using Exclusive OR gate](/images/electronics/circuits/Ex-OR_switch.gif)
Programmable Inverter using Exclusive OR gate
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