149 / 156
Electrical Theory & Applications for HVACR
Glossary
Page 137
milliampere (mA)
one thousandth of an ampere
millivolt (mV)
one thousandth of a volt
momentary switch
a spring loaded control that makes or breaks a circuit only when it is held in place
motor
a device that changes electrical energy to mechanical moƟon
mulƟmeter
a meter capable of two or more electrical quanƟƟes, such as volts, amps, or ohms
N
NaƟonal Electrical Code (NEC)
a naƟonal code wriƩen for the purpose of safeguarding persons and property, sponsored by the
NaƟonal Fire ProtecƟon AssociaƟon
negaƟve charge
the charge that results from an excess of electrons
negaƟve temperature coefficient thermistor (NTC)
a resistor that decreases resistance as temperature increases
neutral
having no charge (line which is grounded at the fuse box)
neutron
a parƟcle with no electrical charge located in the nucleus of an atom
nominal
the average raƟng of power or voltage during normal operaƟon
nonferrous
the group of metals that do not contain iron
normally closed
describes a device that automaƟcally moves to a closed posiƟon when power is removed
normally open
describes a device that automaƟcally moves to an open posiƟon when power is removed