Basic Electronics: Forward Biased PN Junction Diode

Vocabulary flashcards covering the fundamentals of PN junction diodes, depletion layer formation, internal potential barriers, forward biasing mechanisms, and V-I characteristics.

PN Junction Diode

A two-terminal semiconductor device formed by joining a p-type semiconductor with an n-type semiconductor.

Diffusion Current

A negligible current generated solely by the momentary motion of electrons crossing the junction to recombine with and neutralize holes.

Diffusion Process

The process occurring at the junction where free electrons from the n-side and holes from the p-side attract, cross over, and neutralize one another.

Depletion Layer

A region near the junction with a thickness $d$ that is depleted of free charge carriers, consisting entirely of neutral atoms resulting from electron-hole recombination.

Potential Barrier

The internal voltage barrier developed across the depletion layer ($V = E \times d$) that opposes and prevents electrons in the n-type region from crossing into the p-type region.

Potential Barrier of Silicon

The internal barrier potential of a silicon crystal diode, identified in the lecture as $0.6\,\text{eV}$.

Potential Barrier of Germanium

The internal barrier potential of a germanium crystal diode, identified in the lecture as $0.3\,\text{eV}$.

Biasing

The procedure of connecting an external battery or DC power supply across the terminals of a PN junction diode.

Forward Biasing

The connection scheme where the positive terminal of an external battery is connected to the p-type semiconductor and the negative terminal is connected to the n-type semiconductor.

Anode

The p-type semiconductor terminal of the PN junction diode connected to the positive supply.

Cathode

The n-type semiconductor terminal of the PN junction diode connected to the negative supply.

Forward Bias Effect on Depletion Layer

The narrowing or reduction of the depletion layer width due to electrostatic repulsion exerted by the external battery terminals on the majority carriers toward the junction.

Forward Bias Effect on Electric Field

The reduction in net internal electric field across the junction because the external applied electric field opposes the built-in field of the depletion layer.

V-I Characteristics

The graphical relationship between the applied forward voltage ($V_F$) and the resulting forward current ($I_F$) through the PN junction diode.

Knee Voltage (Cut-in / Threshold Voltage)

The specific forward voltage value exceeding the potential barrier at which the diode begins conducting significant forward current.