MOSFETA semiconductor device that contains diffused source and drain regions on either side of a P-
or N-channel area. Also contains a gate insulated from the channel area by silicon-oxide. Operates in
either the depletion or the enhancement mode.
Mu²(QJOLVK VSHOOLQJ IRU WKH *UHHN OHWWHU
NEGATIVE TEMPERATURE COEFFICIENTA characteristic of a semiconductor material, such
as silver sulfide, in which resistance to electrical current flow decreases as temperature increases.
NONLINEARHaving an output that does not rise or fall directly with the input.
NPNAn NPN transistor is formed by introducing a thin region of P-type material between two regions
of N-type material.
OPTICAL COUPLERA coupler composed of an LED and a photodiode and contained in a
light-conducting medium. Suitable for frequencies in the low-megahertz range.
OPTOELECTRONIC DEVICESDevices that either produce or use light in their operation.
OVERDRIVENWhen the input signal amplitude is increased to the point that the transistor goes into
saturation and cutoff.
PENTAVALENT IMPURITYA type of impurity which contains five valence electrons and donates
one electron to the doped material. Also called DONOR IMPURITY.
PHOTOCELLA light-controlled variable resistor that has a light-to-dark resistance ratio of 1:1000.
Used in various types of control and timing circuits.
PHOTODIODEA light-controlled variable resistor. Current flow increases when the PN junction is
exposed to an external light source
PHOTOTRANSISTORAn optoelectronic device that conducts current when exposed to light.
Produces more current and is much more sensitive to light than the photodiode.
PHOTOVOLTAIC CELL (SOLAR CELL)A device that acts much like a battery when exposed to
light and converts light energy into electrical energy.
POINT-CONTACT TRANSISTORA semiconductor diode that can work with and amplify the
ultrahigh frequencies used in radar.
POSITIVE TEMPERATURE COEFFICIENTThe characteristic of a conductor in which the
resistance increases as temperature increases.
POWER SUPPLYA unit that supplies electrical power to another unit. It changes ac to dc and
maintains a constant voltage output within limits.
PRINTED CIRCUIT BOARDA flat insulating surface upon which printed wiring and miniaturized
components are connected in a predetermined design and attached to a common base.
QUANTUM-MECHANICAL TUNNELINGWhen an electron is able to cross a PN junction because
of tunnel effect.
QUIESCENCEThe operating condition of a circuit when no input signal is being applied to the