PEAK VOLTAGEThe maximum value present in a varying or alternating voltage. This may be
positive or negative.
PENTODE TUBEA five-electrode electron tube containing a plate, a cathode, a control grid, and two
PERSISTENCEThe duration of time a display remains on the face of a CRT.
PHOSPHORThe material used to convert the energy of electrons into visible light.
PLANAR TUBEAn electron tube, constructed with parallel electrodes and a ceramic envelope, which
is used at uhf frequencies. It is commonly referred to as lighthouse tube.
PLATE DISSIPATIONThe amount of power lost as heat in the plate of a vacuum tube.
PLATE RESISTANCEThe plate voltage change divided by the resultant plate current change in a
vacuum tube, all other conditions being fixed.
POWER PENTODEA special-purpose tube used to provide high-current gain or power amplification.
Each grid wire is directly in line with the one before and after it, a fact that allows more electrons to
reach the plate.
POWER SUPPLYA unit that supplies electrical power to another unit. It changes ac to dc and
maintains a constant voltage output within limits.
QUIESCENCEThe operating condition of a circuit when no input signal is being applied to the
RECTIFIERA device which, by its construction characteristics, converts alternating current to a
pulsating direct current.
REGULATOR-The section in a basic power supply that maintains the output of the power supply at a
constant level in spite of large changes in load current or in input line voltage.
REMOTE-CUTOFF TUBEAn electron tube in which the control grid wires are farther apart at the
centers than at the ends. This arrangement allows the tube to amplify large signals without being
driven into cutoff. This tube is also called a VARIABLE-mu tube.
rgkThe symbol used to express the resistance between the grid and the cathode of an electron tube.
rpkThe symbol used to represent the variable resistance between the cathode and the plate of a tube.
RIPPLE FREQUENCYThe frequency of the ripple current. In a full-wave rectifier, it is twice the
input line frequency.
RIPPLE VOLTAGEThe alternating component of unidirectional voltage. (This component is small
compared to the direct component).
SATURATIONThe point in a tube where a further increase in plate voltage no longer produces an
increase in plate current. At this point the upper limit of the conduction capabilities of the tube has
SECONDARY EMISSIONThe liberation of electrons from an element, other than the cathode, as a
result of being struck by other high-velocity electrons.