I Recently found the need to add 2 new Digital Logic Gates Circuits to my collection.

There are alot of combinations using the basic logic circuits that can produce
strange effects but there are times when your project just wont work without them so
i hope these 2 will prove to be more than useful.


Transistors used in these circuits can be any npn transistor such as BC547, BC548, BC549, 2N3904 etc.
Diodes can be virtually any type so long as they can handle the reverse voltages in your design.
LED's were only used to provide a visual reference to show these circuits in action.

Experiment on breadboard first before you use any of the circuits shown, All were tested before publishing and All of the component values can easily be played around with to meet your needs.

inputs can be virtually any signal source from timers to oscillators and more, or even push buttons and reed switches and so on.


in both circuits you will notice inputs a and b have 2 terminals, in the built circuits
both A's are connected together and both B's are connected.
all of the 10K resistors can be lower values if you get any problems.



XOR (Exclusive OR)

With a normal OR Gate, one or both of inputs that are used will turn the output on,
but with This XOR Circuit Only one of the 2 inputs are allowed to be used at one time.

If input A or B is switched on then the output is switched on, but if both are used
then the output stays switched off.



XNOR (Exclusive NOR)

With a normal NOR gate, one or both of the inputs will turn the output off,
but like the XOR Gate only one of the XNOR inputs can be used at any one time
to switch the output off.


If input A or B is switched on then the output is switched off, but if both are used
then the output stays switched on.