Power Supplies Vocab

half wave rectifier

A diode rectifier that converts AC to pulsating DC by eliminating either the negative or the positive alternation of each input AC cycle.

crowbar

Circuit used to protect the output of a source from a short circuited load. Load current is limited to a value the source can deliver without damage.

zener diode

Semiconductor diode in which reverse breakdown voltage current causes the diode to develop a constant voltage. Used for voltage regulation.

peak inverse voltage

(PIV) The maximum rated value of a AC voltage acting in the direction opposite to that in which a device is designed to pass current.

silicon-controlled rectifier

(SCR) Three terminal active device that acts as a gated diode. The gate terminal is used to turn the device on allowing current to pass from cathode to anode.

primary

First winding of a transformer. Winding that is connected to the source as opposed to secondary which is a winding connected to a load.

polarity

Term used to describe positive and negative charges.

average value

A value of voltage or current where the area of the wave above the value equals the area of the wave below the value.

surge current

High charging

sine wave

Wave whose amplitude is the sine of a linear function of time. It is plotted on a graph that plots amplitude against time or radial degrees relative to the angular rotation of an alternator.

battery

A DC voltage source containing two or more cells that convert chemical energy to electrical energy.

bridge rectifier

A circuit using four diodes to provide full wave rectification. Converts an AC voltage to a pulsating DC voltage

bleeder current

A current drawn continuously from a source. Bleeder current is used to stabilize the output voltage of a source.

Block diagram

A diagram of a system, a computer, or a device in which the principal parts are represented by suitably annotated geometrical figures to show both the basic functions of the parts and their functional relationships.

fuse

A protective device in the current path that melts or breaks when current exceeds a predetermined maximum value.

autotransformer

A single winding transformer where the output is taken from taps on the winding.

load

A source drives a load. Whatever component or piece of equipment is connected to a source and draws current from a source is a load on that source.

center tapped transformer

A transformer with a connection at the electrical center of a winding

AC voltage

A voltage in which the polarity alternates

DC

Abbreviation for "direct current".

rms

Abbreviation for "root mean square"

mutual inductance

Ability of one indicator's lines of force to link with another inductor.

hysteresis

Amount that the magnetization of a material lags the magnetizing force due to molecular friction. In Schmitt Trigger circuits, the difference between the upper and lower trigger points.

alternating current

An electric current that rises to a maximum in one direction, falls back to zero and then rises to a maximum in the opposite direction and then repeats.

ground

An intentional or accidental conducting path between an electrical system or circuit and the earth or some conducting body acting in place of the earth. A ground is often used as the common wiring point or reference in a circuit.

chassis ground

Connection to a chassis

load current

Current drawn from a source by a load.

direct current

Current that flows in only one direction.

eddy currents

Currents induced into a conducting core due to the changing magnetic field. Eddy currents produce heat which is a loss of power and lowers the efficiency of an inductor.

regulator

Device or circuit that maintains a desired output under changing conditions.

voltage regulator

Device or circuit that maintains constant output voltage (within certain limits) in spite of changing line voltage and/or load current.

rectifier

Diode circuit that converts alternating current into pulsating direct current

power supply

Electrical equipment used to deliver either AC or DC voltage.

technician

Expert in troubleshooting circuit and system malfunctions. Along with a thorough knowledge of test equipment and how to use it to diagnose problems, the technician is also familiar with how to repair or replace faulty components. Technicians basically translate theory into action

ripple frequency

Frequency of the ripple present in the output of a DC source.

slow-blow fuse

Fuse that can withstand a heavy current (up to ten times its rated value) for a small period of time before it opens.

schematic diagram

Illustration of an electrical or electronic circuit with the components represented by their symbols.

transformer

Inductor with two or more windings. Through mutual inductance, current in one winding called a primary will induce current into the other windings called secondaries.

peak

Maximum or highest amplitude level

chassis

Metal box or frame into which components are mounted.

alternator

Name for an AC generator.

63. winding

One or more turns of a conductor wound in the form of a coil

secondary

Output winding of a transformer. Winding that is connected to a load.

solid state

Pertaining to circuits where signals pass through solid semiconductor material such as transistors and diodes as opposed to vacuum tubes where signals pass through a vacuum.

copper loss

Power lost in transformers, generators, connecting wires and other parts of a circuit due to current flow through the resistance of copper conductors.

regulated power supply

Power supply that maintains a constant output voltage under changing load conditions.

rectification

Process that converts alternating current to direct current.

turns ratio

Ratio of the number of turns in the secondary winding of a transformer to the number of turns in the primary winding.

voltage multiplier

Rectifier circuit using diodes and capacitors to produce a DC output voltage that is some multiple of the peak value of AC input voltage. Cost effective way of producing higher DC voltages. Voltage doublers and voltage triplers are examples.

full wave rectifier

Rectifier that makes use of the full AC wave in both the positive and negative half cycles.

rms value

Rms value of an AC sine wave is 0.707 times the peak value. This is the effective value of an AC sine wave. The rms value of a sine wave is the value of a DC voltage that would produce the same amount of heat in a heating element.

sine

Sine of an angle of a right angle triangle is equal to the opposite side divided by the hypotenuse.

cell

Single unit used to convert chemical energy into a DC electrical voltage

jack

Socket or connector into which a plug may be inserted.

troubleshooting

Systematic approach to locating the cause of a fault in an electronic circuit or system.

load regulation

The ability of a voltage regulator to maintain a constant output voltage under varying load currents.

line regulation

The ability of a voltage regulator to maintain a constant voltage when the regulator input voltage varies

percent of regulation

The change in output voltage that occurs between no-load and full-load in a DC voltage source. Dividing this change by the full-load value and multiplying the result by 100 gives percent regulation.

ripple voltage

The small variations in Dc voltage that remain after filtering in a power supply

period

Time to complete one full cycle of a periodic or repeating waveform.

step-up transformer

Transformer in which the output AC voltage is greater than the input AC voltage.

step-down transformer

Transformer in which the output AC voltage is less than the input AC voltage.

supply voltage

Voltage provided by a power source.

percent of ripple

aThe ratio of the effective rms value of ripple voltage to the average value of the total voltage. Expressed as a percentage.