Detecting asymmetry in a bidirectional semiconductor device

A system includes a signal generator, configured to pass a generated signal, which has two different generated frequencies, through a circuit including a bidirectional semiconductor device. The system further includes a processor, configured to identify, while the generated signal is passed through the circuit, a derived frequency, which derives from the generated frequencies, on the circuit, and to generate, in response to identifying the derived frequency, an output indicating that a property of the bidirectional semiconductor device is asymmetric. Other embodiments are also described.