Page 20 - The Illustrated Dictionary of Electronics

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abvolt • accentuation 5

abvolt The unit of potential difference in the cgs acceleration at stall The angular acceleration of a
electromagnetic system. One abvolt equals 10 –8 V servomotor at stall, determined from the stall
and is the difference of potential between any two torque and the moment of inertia of the motor’s
points when 1 erg of work is required to move 1 rotor.
abcoulomb of electricity between them. acceleration derivative Acceleration (a) expressed
abwatt The unit of power in the cgs electromagnetic as the second derivative of distance (s) with re-
2
2
system. One abwatt equals 10 7 W and is the spect to time (t): a equals d s/dt .
power corresponding to 1 erg of work per second. acceleration potential See ACCELERATING
ac 1. Abbreviation of ALTERNATING CURRENT. VOLTAGE.
2. Abbreviation of ATTITUDE CONTROL. 3. Ab- acceleration switch A switch that operates auto-
breviation of AERODYNAMIC CENTER. 4. A suf- matically when the acceleration of a body to
fix meaning AUTOMATIC CALCULATOR or which it is attached exceeds a predetermined rate
AUTOMATIC COMPUTER. in a given direction.
a/c 1. Abbreviation of AIRCRAFT. 2. Abbreviation acceleration time The time required by a com-
of AIR CONDITIONING. puter to take in or deliver information after inter-
Ac Symbol for ACTINIUM. preting instructions. Compare ACCESS TIME.
ACA Abbreviation of automatic circuit analyzer. acceleration torque During the accelerating pe-
ac base current Symbol, I B(ac). The ac component of riod of a motor, the difference between the torque
base current in a bipolar transistor. demanded and the torque actually produced by
ac base resistance Symbol, R B (ac). The dynamic the motor.
base resistance in a bipolar transistor. acceleration voltage The potential between accel-
ac base voltage Symbol, V B(ac). The ac component erating elements in a vacuum tube, the value of
of base voltage in a bipolar transistor. It is the ac which determines average electron velocity.
input signal voltage in a common-emitter ampli- accelerometer A transducer whose output voltage
fier or emitter-follower amplifier. is proportional to the acceleration of the moving
ac bias In a tape recorder, the high-frequency cur- body to which it is attached.
rent that passes through the recording head to accentuation The emphasis of a desired band of
linearize operation. frequencies, usually in the audio-frequency spec-
acc 1. Abbreviation of AUTOMATIC CHROMI- trum.
NANCE CONTROL. 2. Abbreviation of AUTO-
MATIC COLOR COMPENSATION. 3. Abbreviation
of ACCELERATION.
ac cathode current Symbol, I K(ac). The ac compo-
nent of cathode current in an electron tube.
ac cathode resistance Symbol, R K(ac). The dynamic
cathode resistance in an electron tube. R K(ac)
equals dV K/dI K for a constant value of V G.
ac cathode voltage Symbol, V K(ac). The ac compo-
nent of cathode voltage in an electron tube. It is
the ac output signal voltage in cathode-follower
and grounded-grid amplifiers.
accelerated life test A test program that simu-
lates the effects of time on devices or apparatus,
by artificially speeding up the aging process.
accelerated service test A service or bench test in
which equipment or a circuit is subjected to an
extreme condition in an attempt to simulate the
effects of average use over a long time.
accelerating conductor or relay A conductor or
relay that prompts the operation of a succeeding
device in a starting mode according to established
conditions.
accelerating electrode In a cathode-ray tube or
klystron, the electrode to which the accelerating
voltage is applied.
accelerating time The elapsed time that starts
when voltage is applied to a motor, and ends
when the motor shaft reaches maximum speed.
accelerating voltage A positive high voltage applied
to the accelerating electrode of a cathode-ray tube
to increase the velocity of electrons in the beam.