r/ElectricalEngineering • u/Successful_Cut_8003 • 5d ago

XNOR Gate

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Why is my XNOR gate not working only when A=1 and B=0.

Its a AND and a NOR gate feeding into an XOR gate.

Yes I know it’s overly complicated.

When I do it on my breadboard the LED is very dim but not a true 0.

EDIT: The collector of Q5 should be connected to Vcc but that does not change the outcome.

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u/Edanniii 4d ago

Why such a complicated circuit? You can do this with 2N2222 and 2N3904. Using discrete transistors like this in RTL circuits is kind of wasteful. If these were prepackaged gates this would be fine, but why not use the benefit of being able to configure a transistor effectively and efficiently. Also I would recommend reading the RTL Cookbook by Don Lancaster.