18WuD2x

push-push multiplier • PZT 565
Input
push-push
Output
+12 V
but has some merit as an even-harmonic multiplier
(e.g., a doubler or quadrupler). Also see
PUSH-PULL MULTIPLIER.
push-to-talk switch See PRESS-TO-TALK
SWITCH.
pushup list In data processing, a method of
amending a list, whereby new items are added at
the end of the list; all other items retain their original
positions. Compare PUSHDOWN LIST.
pV Abbreviation of PICOVOLT.
PVC Abbreviation of POLYVINYL CHLORIDE.
pW Abbreviation of PICOWATT.
PWM 1. Abbreviation of PULSE-WIDTH MODULA-
TION. 2. Abbreviation of PLATED-WIRE MEM-
ORY.
pwr Abbreviation of POWER.
Pyralin See CELLULOSE NITRATE.
pyramidal horn antenna A rectangular horn antenna
that is flared in two dimensions. The horn
width and height both increase linearly with increasing
distance (in the direction of maximum
radiation/response) from the feed point.
pyramidal wave See BACK-TO-BACK SAWTOOTH.
Pyrex A heat-resistant glass having numerous applications
in electronics and chemistry.
pyrheliometer An instrument used to measure infrared
radiation.
pyroelectricity In certain crystals, electricity generated
by temperature change, and in particular,
by the application of heat.
pyroelectric lamp See NERNST LAMP.
pyroelectric material A crystalline material that
generates an output voltage when it is heated.
pyrolysis The process whereby heat changes a
substance into one of several different substances
by rearranging its atoms.
pyromagnetic effect In a material or circuit, the
combined effect of heat and magnetism.
pyrometer An instrument, other than a thermometer,
used for the measurement of temperature.
See, for example, OPTICAL PYROMETER.
Pythagorean scale A sound scale defining a specific
type of relationship among audio tones. If x
and y are related by the Pythagorean scale and
are adjacent in frequency, then a specific frequency
( f ) exists, so x = f 2 and y = f 3 .
Pythagorean theorem A theorem of plane geometry.
For a right triangle, with sides of lengths a, b,
and c, where c is the side opposite the right angle,
it is always true that a 2 + b 2 = c 2 .
p-zone See P LAYER.
PZM Abbreviation of PRESSURE-ZONE MICRO-
PHONE.
PZT Abbreviation of LEAD ZIRCONATE TITANATE.