TC 9-62
Ruggedness (shock and vibration resistance, high overload capability, and
freedom from effects of moisture).
No warm-up time.
The magnetic amplifier has no moving parts and can be hermetically sealed within a case
similar to the conventional dry-type transformer.
7-99.
The magnetic amplifier also has a few disadvantages. These disadvantages include:
Cannot handle low-level signals.
Not useful at high frequencies
Has a time delay associated with the magnetic effects.
The output waveform is not an exact reproduction of the input waveform (poor
fidelity).
7-100. As mentioned, the magnetic amplifier does not amplify magnetism, but uses
electromagnetism to amplify a signal. It is a power amplifier with a very limited frequency
response. Technically, it falls into the classification of an audio amplifier. However, since
the frequency response is normally limited to 100 Hz and below, the magnetic amplifier is
more correctly called a low-frequency amplifier.
7-101. The basic principle of a magnetic amplifier is very simple (remember, all
amplifiers are current-control devices). A magnetic amplifier uses a changing inductance to
control the power delivered to a load.
BASIC OPERATION OF A MAGNETIC AMPLIFIER
7-102. Figure 7-26 shows a simple circuit with a variable inductor in series with a resistor
(representing a load). The voltage source is 100 volts at 60 Hz.
Figure 7-26. Variable Inductor in Series With a Load
7-36
TC 9-62
23 June 2005
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