How does Fialka manage to have a letter encipher unto itself? http://www.cryptomuseum.com/crypto/fialka/index.htm

Fialka was an electromechanical rotor machine.

How does it manage to have a letter encipher unto itself. I realize it does something clever by using transistors, but it has a reflector. With direct current circuits, there has to be a negative and a positive connector. If one simply attached a positive current to itself, it wouldn't flow. So how does it work?
The reflector wheel on the Fialka incorporates a transistor switching circuit connecting pins 16, 18 and 24. In coding mode, a signal on pin 16 is connected via pin 18, a signal on pin 18 is connected to pin 24, and a signal on pin 24 is connected to pin 16.  In decoding mode, these paths are reversed.  This allows the Fialka to encode any letter as itself, overcoming one of the major weaknesses of the Enigma machine.