Electronics: Semiconductors, Diodes, and Rectification

Vocabulary practice flashcards covering intrinsic and extrinsic semiconductors, charge carrier mechanics, p-n junction diodes, and AC-to-DC rectification methods.

Electrical Conductors

Materials that readily conduct electricity because their valence electrons are not tightly bound to the nucleus and can move freely; examples include copper, aluminium, iron, lead, brass, nychrome, and manganin.

Electrical Insulators

Materials that do not conduct electricity due to strong inter-atomic covalent bonds that leave very few electrons free to move; examples include ebonite, polythene, plastic, dry wood, asbestos, and glass.

Intrinsic Semiconductors

Pure crystalline semiconductor materials, such as silicon ($\text{Si}$) and germanium ($\text{Ge}$), that belong to group IV of the periodic table and have four valence electrons.

Silicon Lattice at $0\,\text{K}$

The state of a pure silicon crystal at absolute zero where all covalent bonds are completely intact and no free electrons or holes exist to conduct electricity.

Temperature Effect on Conductors

An increase in temperature intensifies the random motion of free electrons, which impedes electric current flow, causing a decrease in conductivity and an increase in resistivity.

Temperature Effect on Semiconductors

An increase in temperature provides thermal energy that breaks covalent bonds, releasing free electrons and generating holes, which causes an increase in conductivity and a decrease in resistivity.

Hole

A vacant position with an electron deficiency created when a covalent bond breaks; it carries an unneutralized positive charge from the nucleus and acts as a mobile positive charge carrier.

Electrical Neutrality of Pure Semiconductors

The condition in an intrinsic semiconductor where the total number of free conduction electrons exactly equals the number of holes, keeping the overall lattice electrically neutral.

Extrinsic Semiconductors

Semiconductor materials whose electrical conductivity and charge carrier concentrations have been increased by doping an intrinsic semiconductor with another element.

n-type Semiconductor

An extrinsic semiconductor formed by doping an intrinsic semiconductor with a pentavalent group V element (such as phosphorous, arsenic, or antimony), where free electrons serve as majority carriers.

Donor Atoms

Group V impurity atoms (such as $\text{P}$, $\text{As}$, and $\text{Sb}$) that contribute an extra unbonded electron to the crystal lattice upon bonding with four surrounding silicon atoms.

p-type Semiconductor

An extrinsic semiconductor formed by doping an intrinsic semiconductor with a trivalent group III element (such as boron, aluminium, gallium, or indium), where holes serve as majority carriers.

Acceptor Atoms

Group III impurity atoms (such as $\text{B}$, $\text{Al}$, $\text{Ga}$, and $\text{In}$) with three valence electrons that create an electron deficiency (a hole) capable of receiving an electron.

Majority and Minority Carriers

The dominant and secondary charge carriers in extrinsic semiconductors; in p-type semiconductors, holes are majority carriers and electrons are minority carriers, whereas in n-type semiconductors, electrons are majority carriers and holes are minority carriers.

p-n Junction

The boundary interface formed inside a single semiconductor crystal by doping one side with a group III element (p-type) and the other side with a group V element (n-type).

Junction Diode

A two-terminal electronic device consisting solely of a p-n junction that allows current to flow primarily when connected in the forward-biased direction.

Anode and Cathode

The two terminals of a junction diode, where the anode ($A$) corresponds to the p-type region and the cathode ($K$) corresponds to the n-type region.

Diode Cathode Ring

A white or silver-colored band printed near one end of the black cylindrical body of a junction diode to identify the cathode terminal.

Alternating Current (AC)

An electric current that periodically alternates or reverses its direction of flow through a circuit over time.

Direct Current (DC)

An electric current that flows continuously in only one direction through a circuit.

Rectification

The process of converting an alternating current (AC) into a unidirectional direct current (DC) using components such as junction diodes.

Half Wave Rectification

A rectification circuit utilizing a single diode that permits current to pass only during the positive half cycle of an AC input, producing an output of zero during the negative half cycle.

Full Wave Rectification (Bridge Rectifier)

A rectification method using four diodes arranged in a closed bridge loop so that both half cycles of an alternating current are directed through the load in the same direction.

Diode Voltage Drop in a Bridge Circuit

The potential loss of $2 \times 0.7\,\text{V} = 1.4\,\text{V}$ that occurs across the two conducting diodes during each half cycle of operation in a four-diode bridge rectifier.