- amplifiers are classified
by FUNCTION and
FREQUENCY RESPONSE. Function refers to an amplifier being a
VOLTAGE AMPLIFIER or a POWER AMPLIFIER. Voltage amplifiers
provide voltage amplification and power amplifiers provide power
amplification. The frequency response of an amplifier can be described by
classifying the amplifier as an AUDIO AMPLIFIER, RF AMPLIFIER, or
VIDEO (WIDE-BAND) AMPLIFIER. Audio amplifiers have frequency
response in the range of 15 Hz to 20 KHz. An RF amplifier has a frequency
response in the range of 10 KHz to 100,000 MHz. A video (wide-band)
amplifier has a frequency response of 10 Hz to 6 MHz.
CLASS OF OPERATION - the class of operation of a transistor amplifier is
determined by the percent of time that current flows through the transistor in
relation to the input signal.
CLASS A OPERATION - where transistor current flows for 100 percent (360) of
the input signal. Class A operation is the least efficient class of operation, but
provides the best fidelity.
23 June 2005