Body that can be used to attract or repel magnetic
materials.
magnetic circuit breaker
Circuit breaker that is tripped or activated by use of
an electromagnet.
magnetic coil
Spiral of a conductor which is called an electromagnet.
magnetic core
Material that exists in the center of the mahnetic coil
to either physically support the windings (non-magnetic
material) or to concentrate the magnetic flux (magnetic
material).
magnetic field
Magnetic lines of force travelling from the north pole
to the south pole of a magnet.
magnetic flux
The magnetic lines of force produced by a magnet.
magnetic leakage
The passage of magnetic flux outside the path along
which it can do useful work.
magnetic poles
Points of a magnet from which magnetic lines of force
leave (north pole) and arrive (south pole).
magnetism
Property of some materials to attract or repel others.
magnetizing force
Also called magnetic field strength. It is the
magnetomotive force per unit length at any given point
in a magnetic circuit.
magnetomotive force
Force that produces a magnetic field.
majority carriers
The conduction band electrons in an n-type material and
the valence band holes in a p-type material. Produced by
pentavalent impurities in n-type material and trivalent
impurities in p-type material.
matched impedance
Condition that occurs when the output impedance of a
souce is equal to the input impedance of a load.
matching
Connection of two components or circuits so that maximum
power is transferred between the two.
maximum power transfer
A theorem that states that maximum power will be
transferred from source to load when input impedance of
the load equals the output impedance of the source.
Maxwell
Unit of magnetic flux. One maxwell equals one magnetic
line of force.
mercury cell
Primary cell using a mercuric oxide cathode, a zinc
anode and a potassium hydroxide electrolyte.
metal film resistor
A resistor in which a film of metal oxide or alloy is
deposited on an insulating substrate.
metal oxide field effect transistor
(MOSFET) A field effect transistor in which the
insulating layer betwen the gate electrode and the
channel is a metal oxide layer.
metal oxide resistor
A metal film resistor in which an oxide of metal (such
as tin) is deposited as a film onto the substrate.
meter
Any electrical or electronic measuring device. In the
metric system, it is the unit of length equal to 39.37
inches.
meter FSD current
Value of meter current needed to cause the needle to
deflect to its maximum position (full scale deflection).
meter resistance
DC resistance of the meter's armature coil.
mica capacitor
Capacitor using mica as the dialectric.
microphone
Electroacoustic transducer that converts sound energy
into elecric energy.
microwave
Band of very short wavelength radio waves within the
UHF, SHF and EHF bands.
midband gain
Gain of an amplifier operating within its bandwidth.
mid-point bias
An amplifier biased at the center of its DC load line.
mil
One thousandth of an inch (0.001 in.)
Miller's theorem
A theorem that allows you to represent a feedback
capacitor as equivalent input and output shunt
capacitors.
minority carriers
The conduction band holes in n-type material and valence
band electrons in p-type material. Most minority
carriers are produced by temperature rather than by
doping with impurities.
mismatch
Term used to describe a difference between the output
impedance of a source and the input impedance of a load.
A mismatch prevents the maximum transfer of power from
source to load.
modulation
Process by which an information signal (audio for
example) is used to modify some characteristic of a
higher frequency wave known as a carrier (radio for
example).
molecule
Smallest particle of a compound that still retains its
characteristics.
monostable multivibrator
A nultivibrator with one stable output state. When
triggered, the circuit output will switch to the
unstable state for a predetermined period of time and
then return to the stable state. A timer.
MOSFET
Abbreviation for "metal oxide field effect transistor"
also known as an "insulated gate field effect
transistor). A field effect transistor in which the
insulating layer betwen the gate electrode and the
channel is a metal oxide layer.
moving coil loudspeaker
Loudspeaker that uses a moving "voice coil" placed
within a fixed magnetic field. Audio frequency current
in the voice coil causes movement which is mechanically
transferred to the speaker cone. Also known as a dynamic
loudspeaker.
moving coil microphone
Microphone that uses a moving coil within a fixed
magnetic field. Dynamic microphone.
moving coil pick-up
Dynamic phonograph pick-up in which the stylus causes a
coil to move within a fixed magnetic field.
multimeter
Electronic test equipment that can perform multiple
tasks. Typically one capable of measuring voltage,
current and resistance. More sophisticated modern
digital multimeters also measure capacitance,
inductance, current gain of transistors and/or anything
else that can be measured electronically.
multiplier resistor
Resistor connected in series with a moving coil meter
movement to extend the voltage ranges.
multisegmant display
Device made of several light emitting diodes arranged in
a numeric or alphanumeric pattern. By lighting selected
segments numeric or alphabet characters can be
displayed.
multivibrator
A class of circuits designed to produce square waves or
pulses. Astable multivibrators produce continous pulses
without an external stimulus or trigger. Monostable
multivibrators produce a single pulse for some
predetermind period of time only when triggered.
Bistable multivibrators produce a DC output which is
stable in either one of two states. Either high or low.
An external stimulus or trigger is required for the
bistable circuit to change states, either high to low or
low to high.
mutual inductance
Ability of one inductor's lines of force to link with
another inductor.