logic gates

I don't like electronics at all.However,it's an interesting question.For OR operation standard circuit,there are two diodes which are forward biased in 1-1 state.I cannot draw the circuit here;but anyone familiar to the circuit undearstands that even if the two diodes were not there, the OR operation could be performed.Then what is the function of those diodes?

 

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In which case ask somebody familar with the circuit;
"even if the two diodes were not there" makes no sense otherwise.

It is possible to connect the collectors of two transistors to a common load but you can't usually feed two amp ouputs into an input because the outputs then feed into each other and burn out.

 

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Is this the circuit you mean? (positive logic)

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(from HyperPhysics)


If the diodes weren't there, then the two inputs and the output would all be tied to the same voltage. If you tried to set A high and kept B tied to ground, then you'd have a short circuit to ground and A would stay low.

 

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To Pete,I thank you.

 

Stated another way ....
they isolate the inputs from themselves and the outputs.