PICOA prefix adopted by the National Bureau of Standards meaning 10
PICTORIAL DIAGRAMA diagram showing actual pictorial sketches of the various parts of an
equipment and the electrical connections between the parts .
PIEZOELECTRIC EFFECTThe effect of producing a voltage by placing a stress, either by
compression, expansion, or twisting, on a crystal and, conversely, producing a stress in a crystal by
applying a voltage to it .
PIP (BLIP)On a CRT display, a spot of light or a baseline irregularity representing the radar echo .
PITCHA term used to describe the frequency of a sound heard by the human ear .
PLANAR TUBEAn electron tube, constructed with parallel electrodes and a ceramic envelope, that is
used at uhf frequencies. It is commonly referred to as a lighthouse tube .
PLANE OF POLARIZATIONThe plane (vertical or horizontal), with respect to the earth, in which the
E field propagates .
PLANE WAVEFRONTSWaves of energy that are flat, parallel planes and are perpendicular to the
direction of propagation .
PLANNED-POSITION INDICATORA radar display in which range is indicated by the distance of a
bright spot or pip from the center of the screen and the bearing is indicated by the radial angle of the
PLATE(1) One of the electrodes in a storage battery . (2) One of the electrodes in a capacitor . (3)
The principal electrode to which the electron stream is attracted in an electron tube .
PLATE DISSIPATIONThe amount of power lost as heat in the plate of a vacuum tube .
PLATE KEYINGA keying system in which the plate supply is interrupted .
PLATE MODULATORAn electron-tube modulator in which the modulating voltage is applied to the
plate circuit of the tube .
PLATE RESISTANCEThe plate voltage change divided by the resultant plate current change in a
vacuum tube, all other conditions being fixed .
POINT BENDERA tool used to adjust the contact spacing on a relay .
POINT-CONTACT DIODEA diode in which the end of a fine wire is pressed against a semiconductor.
Used as a detector or mixer over the microwave region .
POINT OF ZERO DISPLACEMENTSee REFERENCE LINE .
POINT-TO-POINT WIRINGIndividual wires run from terminal to terminal to complete a circuit .
POLARThe teletypewriter operation in which current flow of one polarity represents a mark, and current
of the opposite polarity represents a space .
POLAR-COORDINATE GRAPHA graph with a pair of axes. One consists of a series of circles with a
common center, and the other consists of a rotating radius extending from the center of the concentric