From the 1960s to the 1980s, most monitor speaker cabinets used an external power amplifier.

Another way of adding range uses a power amplifier.

The band worked by setting up all the instruments with only a single power amplifier.

High power optical amplifiers are used in long distance systems.

Next is the power amplifier to produce the output wave.

This thing here is the generator of those waves and a very heavy power amplifier.

The problem was in the low voltage circuit internal to the power amplifier.

Engineers were not immediately able to explain the problem, so they turned off the power amplifier for about three hours.

The power amplifier provides the higher current necessary to drive loudspeakers.

This power amplifier, it turned out to be sort of amazing.