——————————————————————————– Quote: ——————————————————————————————————- Originally Posted by MDShunk Since relay #2 is unaffected, I think it’s safe to say that D1 isn’t the issue. Now, on the other hand, if relay #1 only failes to drop out when relay #2 is powered, then I’d guess that you have a “leaky” diode on your hands, passing enough holding current the wrong direction to keep relay #1 closed even after its contact is opened. ———————————————————————————————————- Thank you very much. Your answer is correct completely. Indeed in semiconductor diode, the reverse leakage current is usually specified at a voltage and temperature. Also in general, the conclusion of higher the current carrying capability of the diode is the higher the leakage current. In this case the higher reverse leakage current can to hold auxiliary relay no.1 via contact C2.
