AI-2
FREQUENCY CUTOFF—The frequency at which the filter circuit changes from an action of rejecting
the unwanted frequencies to an action of passing the desired frequencies. Conversely, the point at
which the filter circuit changes from an action in which it passes the desired frequencies to an action
in which it rejects the undesired frequencies.
FREQUENCY STABILITY—Refers to the ability of an oscillator to accurately maintain its operating
frequency.
HALF-POWER POINT—Point on either side of resonance curve at which the power is approximately
70 percent of the maximum value.
HARMONIC—Integral multiples of a fundamental frequency. For example, the harmonics of 60 hertz
are 120 hertz, 180 hertz, 240 hertz, and so forth.
HIGH-PASS FILTER—A filter that passes a majority of the high frequencies on to the next circuit and
rejects, or attenuates, the lower frequencies. Also called a low-frequency discriminator.
INDUCTIVE REACTANCE—The opposition to the flow of an alternating current (expressed in ohms)
caused by the inductance of a circuit. The symbol for inductive reactance is XL.
IMPEDANCE—Total opposition to alternating current flow. Impedance may consist of any combination
of resistance, inductive reactance, and capacitive reactance. The symbol for impedance is Z.
LIMITER—A device which prevents (limits) a waveform from exceeding a specified value.
LOWER-FREQUENCY CUTOFF—The lowest frequency a circuit will pass.
LOW-PASS FILTER—A filter that passes a majority of the low frequencies on to the next circuit and
rejects, or attenuates, the higher frequencies. Also called a high-frequency discriminator.
MULTIVIBRATOR—A form of relaxation oscillator which comprises two stages that are coupled so
that the input of one is derived from the output of the other.
MONOSTABLE MULTIVIBRATOR—A multivibrator which has one steady state. A signal (trigger)
must be applied to cause change of states.
NATURAL FREQUENCY—See Resonance Frequency.
NEGATIVE CLAMPER—The upper extremity of the output waveshape is clamped to a dc potential of
0 volts.
OSCILLATOR—An oscillator is a nonrotating device which produces alternating current. The
frequency is determined by the characteristics of the device.
PARALLEL LIMITER—A resistor and diode connected in series with the input signal. The output is
taken across the diode.
PARALLEL-NEGATIVE LIMITER—A resistor and diode connected in series with the input signal.
The output is taken across the diode and the negative alternation is eliminated.
PARALLEL-POSITIVE LIMITER—A resistor and diode connected in series with the input signal.
The output is taken across the diode and the positive alternation of the input signal is eliminated.
