Question

Why is reciprocity theorem not applicable to unilateral elements?

Answer 1

Unilateral elements such as diode, transistor are also non linear elements.

Reciprocity theorem is based on the fact that resistance in both loops remains the same.

But in case of non-linear elements, the resistance does not remain the same and Ohm's Law is not applicable.

So there is no guaranty that the ratio of voltage and current of two loops will remain the same.

So, we do not apply reciprocity theorem in case of unilateral elements.