Mysterious circuit diagram, there is a transformer painted horizontally, Delta recruitment research and development topic.

A) Release the resistor, and release the voltage on the capacitor after power failure.

B) a filter capacitor, which filters the half-wave pulse voltage rectified by the diode into a relatively flat DC voltage.

C) bypass capacitor. The power supply has two isolated ground wires in DC. Through the bypass capacitor, the two ground wires are AC connected.

D) Rectifier diode, which changes the input alternating current into pulsating direct current.

E) high-frequency choke, so that the high-frequency components in the output DC are less (blocked by it).

This circuit is an additional power supply circuit for small signal high frequency amplification (or processing) equipment.