Interval between two sounds
whose fundamental frequencies
differ by a ratio of 2 to 1. 440
Hz. is one octave above 220 Hz.
offset null
An op amp control pin used to
eliminate the effects of
internal component voltages on
the output of the device.
ohm
Unit of resistance symbolized by
the Greek capital letter omega
(W).
ohmmeter
Device used to measure
electrical resistance.
Ohm's law
Relationship between voltage,
current and resistance. Ohm's
law states that current in a
resistance varies in direct
proportion to voltage applied
and inversely proportional to
resistance.
Ohms per volt
Refers to a value of ohms per
volt of full scale defection for
a moving coil meter movement.
The number of ohms per volt is
the reciprocal of the amount of
current required to produce full
scale deflection of the needle.
A meter requiring 50 microamps
for full scale deflection has an
internal resistance of 20 kW per
volt. The higher the ohms per
volt rating, the more sensitive
the meter.
one-shot
Monostable multivibrator.
op-amp
Abbreviation for operational
amplifier.
open loop gain
Gain of an amplifier when no
feedback is present.
open loop mode
An amplifier circuit having no
means of comparing the output
with the input. (No feedback.)
operational amplifier
A high gain DC amplifier that
has a high input impedance and a
low output impedance. Op-amps
are the most basic type of
linear integrated circuits.
oscillate
To produce a continuous output
waveform without an input signal
present.
oscillator
An electronic circuit that
produces a continuous output
waveform with only DC applied.
oscilloscope
An instrument used to display a
signal graphically. Shows signal
amplitude, period and waveshape
in addition to any DC voltage
present. A multiple trace
oscilloscope can show two or
more waveforms at the same time
for phase comparison and timing
measurements.
out of phase
When the maximum and minimum
points of two or more waveshapes
do not occur at the same time.
output
Terminal at which a component,
circuit or piece of equipment
delivers current, voltage or
power.
output impedance
Impedance measured across the
output terminals of a device
without a load connected.
output power
Amount of power a component,
circuit or system can deliver to
a load.
overload
Condition that occurs when the
load is greater than the system
was designed to handle. (Load
resistance too small, load
current too high.) Overload
results in waveform distortion
and/or overheating.
overload protection
Protective device such as a fuse
or circuit breaker that
automatically disconnects a load
when current exceeds a
predetermined value.
