This is a schematic of the electrical system of a microwave oven that uses a mechanical timer. It is so simple that hesitate to use the term electronic, because there are really only two components that are more than electrical: the magnetron and the high voltage rectifier diode. The capacitor is a high voltage capacitor, and could be found in an electrical system. Here it is used, along with the rectifier and magnetron, as a half wave voltage doubler, with the actual load being the magnetron, which acts as both a rectifier and load resistance. The rest of the circuitry is simply electrical. This makes it very easy to understand.