answer：

A, communication electronic equipment: high frequency increases, filtering appliances, transmitting circuit.
B, a computer: CPU board, a diskette drive, power supply units, etc.
C, audio equipment: input, output amplifier, balanced amplifier, audio amplifier, preamplifier, power amplifier, etc.
D, power equipment, switching regulator, DC/AC converter, SW regulator, etc.
E, power module, inverter, solid relay, rectifier bridge, etc.
F, office automation equipment, motor drives, etc.
G, automobile electronic regulator, ignition, power controller, etc.