ECE TERMS

also known as trivalent and it is the atom that can take an electron

ACCEPTOR ATOM

the smallest particle of an element that retains the properties of that element

ATOM

elements in the periodic table are arranged according to this

ATOMIC NUMBER

multiplication of conduction electrons

AVALANCHE

occurs when VB is > 5V

AVALANCHE BREAKDOWN

necessary because electronic circuits require a constant source of a DC voltage and current to provide power and biasing for proper operation.

FILTERING

escaped valence electron

FREE ELECTRONS

allows unidirectional (one-way) current through the load during the entire 360 of the input cycle, whereas a half-wave rectifier allows current through the load only during one-half of the cycle.

FULL-WAVE RECTIFIER

most frequently used in the construction of electronic devices

Ge, Si, and GaAs

The process of removing one-half the input signal to establish a dc level

HALF-WAVE RECTIFICATION

the condition that essentially prevents current through the diode.

REVERSE BIAS

an indication of the effectiveness of the filter

RIPPLE FACTOR

variation in the capacitor voltage due to the charging and discharging

RIPPLE VOLTAGE

changes ac voltages based on the turns ratio between the primary and secondary

TRANSFORMER

often used to couple the ac input voltage from the source to the rectifier as shown in the figure.

TRANSFORMER

- contribute to the sharp change in the characteristic of a diode - occurs because there is a strong electric field in the region of the junction that can disrupt the bonding forces within the atom and "generate" carriers

ZENER BREAKDOWN

occurs when VB is < 5V

ZENER BREAKDOWN

a silicon pn junction device that is designed for operation in the reverse- breakdown region

ZENER DIODE

diodes that employ the unique portion of the characteristic of a p-n junction

ZENER DIODES

the sharp change in the characteristic at any level

ZENER REGION

a type of full-wave rectifier that uses two diodes connected to the secondary of a center-tapped transformer.

CENTER-TAPPED RECTIFIER

they have a capacitor connected directly from input to output with a resistive element in parallel with the output signal.

CLAMPING NETWORKS

diodes were discovered

1939

transistors were discovered

1947

first silicon transistor was introduced

1954

- converts 220V, 60 Hz ac voltage available at wall outlets into a constant dc voltage - generally the ac input line voltage is stepped down to a lower ac voltage with a transformer

DC POWER SUPPLY

- the region where two layers of positive and negative ions form - a very thin layer compared to the p-region and n-region

DEPLETION REGION

the capacitance involved when excess charge builds up a potential difference across the junction, which in turn creates a capacitance-like effect

DIFFUSION CAPACITANCE

• It was formed when a block of silicon was doped part of it with trivalent and other part with a pentavalent impurity. • is a device that conducts current only in one direction.

DIODE

- to bias a diode, you apply a dc voltage across it

DIODE BIASING

also known as pentavalent and it is the atom that gives up electron

DONOR ATOM

the process that increases the number of current carriers (electrons or holes)

DOPING

the resistance changes as you move along the V-I curve

DYNAMIC OR AC RESISTANCE

forces between opposite charges that form a field of charges

ELECTRIC FIELD

This movement of free electrons is one type of current in a semiconductive material

ELECTRON CURRENT

flow of free electrons

ELECTRON CURRENT

the hole created for every electron raised to conduction band by external energy

ELECTRON-HOLE PAIR

This is the amount of energy that a valence electron must have in order to jump from the valence band to the conduction band.

ENERGY GAP OR BAND GAP

eliminates the fluctuations in the rectified voltage and produces a relatively smooth dc voltage

FILTER

parallel variety has the diode in a branch parallel to the load.

PARALLEL CLIPPERS

forms when a piece of intrinsic silicon is doped so that part is n-type and the other part is p-type

PN JUNCTION

the process when electrons in conduction band loses energy an it goes back to the hole

RECOMBINATION

converts the ac input voltage to a pulsating dc voltage, called a half-wave rectified voltage

RECTIFIER

a circuit that maintains a constant dc voltage for variations in the input line voltage or in the load

REGULATOR

extremely small current that exists in reverse bias caused by the minority carriers in the n and p regions that are produced by the thermally generated electron-hole pairs

REVERSE CURRENT

- also known as reverse current - the current that exists under reverse-bias condition

REVERSE SATURATION CURRENT (Is)

undesirable, thus the smaller the ripple the better the filtering action is.

RIPPLE

materials that is between conductors and insulators in its ability to conduct electrical current

SEMICONDUCTORS

series configuration is defined as one where the diode is in series with the load.

SERIES CLIPPERS

the amount of voltage required to move an electron through the electric field

BARRIER POTENTIAL

it refers to the use of a DC voltage to establish certain operating conditions for an electronic device.

BIAS

if the external reverse bias voltage is increased to this value, the reverse current will drastically increase

BREAKDOWN VOLTAGE

a network constructed of a diode, a resistor, and a capacitor that shifts a waveform to a different dc level without changing the appearance of the applied signal.

CLAMPER

- also known as diode limiters - networks that employ diodes to "clip" away a portion of an input signal without distorting the remaining part of the applied waveform.

CLIPPERS

constructed of two or more semiconductor materials of different atomic structures. Example: GaAs, CdS, GaN, GaAsP

COMPOUND

materials that easily conduct current

CONDUCTORS

Bonding of atoms strengthened by the sharing of electrons.

COVALENT BONDING

materials that does not conduct electrical current under normal condition

INSULATORS

process of losing a valence electron

IONIZATION

- used to model the voltage-current (V-I) characteristic of a semiconductor diode - describes the relationship between the current flowing through the diode and the voltage across it

SHOCKLEY'S DIODE EQUATION

• have improved temperature sensitivity • One of the most abundant materials on earth • Has the benefit of years of development • Is the leading semiconductor materials for electronic components and ICs

SILICON

typical values of barrier potential at 25 deg C

SILICON = 0.7 V GERMANIUM = 0.3 V

have repetitive crystal structure ex: Ge and Si

SINGLE CRYSTAL

specifies how much change occurs in the output voltage for a given change in the input voltage

LINE REGULATION

used to analyze diode circuit using its actual characteristics.

LOAD LINE ANALYSIS

specifies how much change occurs in the output voltage over a certain range of load current values, usually from minimum current (no load) to maximum current (full load)

LOAD REGULATION

two types of semiconductor

SINGLE CRYSTAL COMPOUND

Two categories of impurities

N-TYPE P-TYPE

electrons on the valence shell

VALENCE ELECTRON

the outermost shell of an atom

VALENCE SHELL

power supplies is usually done with integrated circuit voltage regulators

VOLTAGE REGULATION

- prevents changes in the filtered DC voltage due to variations in input voltage or load - connected to the output of a filtered rectifier and maintains a constant output voltage (or current) despite changes in the input, the load current, or the temperature.

VOLTAGE REGULATOR