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degenerate semiconductor • deka- 175
degenerate semiconductor A semiconductor that
behaves like a metal over a wide range of temperatures.
degeneration In an amplifier, the technique of
feeding a portion of the output back to the input
out of phase with the input signal, to improve fidelity
at the expense of gain. Also called negative
feedback or inverse feedback. Compare REGEN-
ERATION.
degenerative resistor An unbypassed emitter resistor
in a common-emitter bipolar-transistor
circuit, or an unbypassed source resistor in a
common-source field-effect transistor circuit.
Signal current flowing through the resistor
produces negative feedback current (degeneration),
which reduces the gain of the stage, but
increases the linearity of the transfer characteristic.
In
degenerative resistor
+
Degenerative
resistor
Out
degradation 1. Gradual deterioration in the condition
or performance of a circuit or device. 2. In a
computer system, compromised performance
caused by component failure.
degradation failure Failure occurring at the terminal
point of degradation.
degraded operation See DEGRADATION.
degreaser See ULTRASONIC CLEANING TANK.
degree 1. A unit of circular angular measurement
equal to 1 /360 of the circumference of a circle. Also
called GEOMETRIC DEGREE. 2. A unit of
temperature measurement. See DEGREE
ABSOLUTE, DEGREE CELSIUS, DEGREE CENTI-
GRADE, DEGREE FAHRENHEIT, and DEGREE
REAUMUR.
degree absolute Symbol, K. The unit of temperature
on the absolute scale. Also see ABSOLUTE
SCALE.
degree Celsius Symbol, °C. The unit of temperature
on the CELSIUS SCALE.
degree centigrade Symbol, °C. The unit of temperature
on the centigrade scale (now called CEL-
SIUS SCALE).
degree Fahrenheit Symbol, °F. The unit of temperature
on the FAHRENHEIT SCALE.
degree of current rectification For a rectifier, the
ratio of the average direct output current to the
root-mean-square (rms) alternating input current.
degree of voltage rectification For a rectifier, the
ratio of the average direct-current (dc) output
voltage to the root-mean-square (rms) alternating-current
(ac) input voltage.
degree Reaumur Symbol, °R. The unit of temperature
on the REAUMUR SCALE.
degrees of freedom 1. The ways in which a point
can move or a system can change. In threedimensional
space, a rigid body has six degrees of
freedom: motion in three linear directions, and
rotation around three linear axes extending
through its center. 2. The ways in which a robot
arm can move, including linear motion and rotational
motion.
degrees of rotation A measure of the extent to
which a robot joint, or a set of robot joints, can be
turned. Some reference axis is always used; angles
are specified in degrees, relative to that axis.
degrees-to-radians conversion The conversion of
angles in degrees to angles in radians. To change
degrees to radians, multiply degrees by 0.01745.
Compare RADIANS-TO-DEGREES CONVER-
SION.
deion circuit breaker A circuit breaker in which
the arc occurring when the contacts open is
quickly extinguished by an external magnetic device.
deionization The conversion of an ionized substance,
such as a gas, to a neutral (non-ionized)
state. The process changes the ions into uncharged
atoms.
deionization potential The voltage at which an
ionized substance becomes deionized; for example,
the voltage at which a glow discharge is extinguished
when the gas ions become neutral
atoms at that voltage. Also called extinction potential.
deionization time The time required for an ionized
gas to become neutral after the removal of the
ionizing voltage.
deionization voltage See DEIONIZATION POTEN-
TIAL.
deionize To restore to an electrically neutral condition
(i.e., to convert ions to neutral atoms, as in
the deionization of the gas when the discharge in
a glow tube is extinguished).
deka- A prefix meaning ten(s) (e.g., DEKAMETER).