31 terms

joule heat

term for the heat generated by current when it passes through a resistance

power

term for the time rate of work

house current

term for the current furnished by electric power companies

rate, resistance

The effective value of an alternating current is regarded as equal to the direct current that would produce heat at the same average ___ in the same _____.

root-mean-square (rms) value

term for the effective value of an alternating current

capacitance

term for the maximum charge that a plate can hold

capacitor

term for a charge-storing device consisting of two conductors in near relation but not touching

farad

the unit of capacitance

microfarads, picofarads

Because they typically store only very small amounts of charge, capacitors usually have capacitances measured in _____ or _____.

area, closer together, dielectric

Capacitance may be changed by:

1.) Increasing the ___ of each plate.

2.) Bringing the plates ____ _____.

3.) Filling the gap between the plates with _____.

1.) Increasing the ___ of each plate.

2.) Bringing the plates ____ _____.

3.) Filling the gap between the plates with _____.

dielectric

term that describes a material that reduces the voltage associated with a given state of charge

dielectric constant

term for the factor by which capacitance is multiplied when a certain material is used as a dielectric

dielectric strength

term for the maximum potential gradient that a material can withstand before it begins to conduct current

self-induced emf

If a change in magnetic flux arises from a fluctuation of current within the conducting loop itself, ______ ___ is produced.

opposes

An induced emf ____ the change inducing it.

self-inductance

term for the tendency of a loop or a coil to oppose any change in current

inductor

term for a circuit element with the property of self-inductance

henry

the unit of inductance

primary, secondary

If two coils in separate circuits are brought close together, changing current in the first (____) coil induces a current in the second (______) coil.

mutual inductance

term for the induction of an emf in one coil by another coil

inductance

term for the combined effect of both mutual inductance and self-inductance

henrys

Mutual inductance is measured in ____.

packing density

term for the number of turns per unit length of a coil

series-aiding combination

term for an arrangement in which the self-inductance in each coil is enhanced by mutual inductance because all the magnetic flux in both coils runs in the same direction

series-opposing combination

term for an arrangement in which self-inductance and mutual inductance have contrary effects

transformer

term for a device for producing a fixed increase or decrease in voltage

transformer equation

term for the equation that relates the voltages and numbers of turns in the primary and secondary coils of a transformer

step-up transformer

term for a transformer that increases voltage

step-down transformer

term for a transformer that decreases voltage

ninety-five

A well-designed transformer transmits energy from the primary circuit to the secondary circuit with above _____ percent efficiency.

Joseph Henry

the physicist who experimented with electricity and magnetism and discovered electromagnetic induction independently of Faraday