Amplifier

摘要

An amplifier for a portable telephone of the like is repaired or replaced without loss of an amplifying function even when the amplifier malfunctions. A plurality of door-shaped amplifier parts are provided on the left and right sides of an amplifier box. The left and right door-shaped amplifier parts can be mounted on opposite sides to each other. One amplifier part is in service and the other amplifier part is a backup. In a case where the amplifier part in service malfunctions, the other amplifier part is used or is mounted for use on the opposite side.