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T U V
Objective. The very
first optical element at the front of a lens.
Ocular. The very last
optical element at the back of a lens (the one closest to the detector).
Ohm. The unit of resistance.
The electrical resistance between two points of a conductor
where a constant difference of
potential of 1 Volt applied between these points
produces in the
conductor a current of 1 Ampere,
the conductor not being the source of any electromotive
It can be represented by the formula
V = I x R, where: V = Voltage I = Current R = Resistance.
Oscilloscope (also CRO, from
Cathode Ray Oscilloscope).
An electronic device that can
display changes of voltage on the
vertical scale against time horizontally. The single most
important piece of test equipment
A video monitor condition in which the raster extends slightly beyond
edges of the CRT screen, cutting
off the outer edges of the picture.
The impedance a device presents to its load. The impedance
the output terminals of a transducer
with the load disconnected and all
impressed driving forces
taken as zero.