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Previous set of "P" definitions and terms.
PEAK AMPLITUDE. The maximum value above or below a reference line.
PEAK CURRENT. The maximum current that flows during a complete cycle.
PEAK DETECTION. Detection that uses the amplitude of pam or the duration of pdm to charge a holding
capacitor and restore the original waveform.
PEAKING COIL. An inductor used in an amplifier to provide high-frequency compensation, which
extends the high-frequency response of the amplifier.
PEAK POWER. The maximum value of the transmitted pulse.
PEAK-REVERSE VOLTAGE. The peak ac voltage that a rectifier tube will withstand in the reverse
direction.
PEAK-TO-PEAK. The measure of absolute magnitude of an ac waveform, measured from the greatest
positive alternation to the greatest negative alternation.
PEAK VALUE. The maximum instantaneous value of a varying current, voltage, or power. It is equal to
1.414 times the effective value of a sine wave.
PEAK VOLTAGE. The maximum value present in a varying or alternating voltage. This value may be
positive or negative.
PENTODE TUBE. A five-electrode electron tube containing a plate, a cathode, a control grid, and two
grids.
PERCENT OF MODULATION. The degree of modulation defined in terms of the maximum permissible
amount of modulation.
PERIGEE. The point in the orbit of a satellite closest to the earth [center].
PERIOD TIME. The time required to complete one cycle of a waveform.
PERIODIC WAVE. A waveform that undergoes a pattern of changes, returns to its original pattern, and
then repeats the same pattern of changes. Examples are square waves, rectangular waves, and sawtooth
waves.
PERIPHERAL DEVICE. In a data processing system, any equipment, distinct from the central processing
unit, that may provide the system with additional capabilities.
PERISCOPE. An optical instrument, housed in a long tube; used to translate the observer's line of
sight in a vertical direction.
PERMANENT MAGNET SPEAKER. A speaker with a permanent magnet mounted on soft iron pole
pieces. [Speaker Manufacturers]
PERMANENT MAGNET MOTOR. A PM motor uses a permanent magnet instead of armature windings. The permanent magnets are mounted [embedded] on the rotor. Permanent Magnet [PM] motors are normally small and produce little horsepower. Manufacturers
PERMEABILITY. The measure of the ability of a material to act as a path for magnetic lines of force.
PERSISTENCE. The length of time a phosphor dot glows on a CRT before disappearing. [CRT Definition]
Next page of "P" Terms and definitions
