ENGG212 - Electronics, Measurements and Transducers Flashcards

A set of 55 practice flashcards covering vocabulary and core concepts related to diode devices, rectification, clippers, LEDs, and Zener regulators based on the lecture notes.

Diode

A two terminal (anode and cathode) PN junction semiconductor that allows only a unidirectional flow of signal (current).

Anode

The positive terminal or electrode of a diode, often associated with the p-type side of a PN junction.

Cathode

The negative terminal or electrode of a diode, often associated with the n-type side of a PN junction.

Forward Biased

The condition where the anode is made positive with respect to the cathode, allowing electricity to flow through the diode.

Reverse Biased

The condition where the anode is made negative with respect to the cathode, blocking the flow of electricity.

Peak Inverse Voltage (PIV)

The maximum reverse voltage that a diode can withstand without breaking down or passing a large current in the reverse direction.

Thermionic Valve

An early type of diode based on vacuum tube technology, which may include auxiliary terminals for a heater.

Schottky Diode

A type of semiconductor diode formed from the contact between a metal and a semiconductor rather than a PN junction.

PN Junction

A junction formed by placing n-type and p-type extrinsic semiconductors together within a single crystal.

Extrinsic Semiconductor

A semiconductor material based on a pure silicon or germanium substrate doped with impurities to create n-type or p-type components.

n-type component

A part of a semiconductor doped with group five elements to create a surplus of electrons as charge carriers.

p-type component

A part of a semiconductor doped with group three elements to create a surplus of holes as charge carriers.

Depletion Region

An area near the junction in a PN semiconductor that has no mobile charge carriers and opposes the flow of electrons and holes.

Dynamic Equilibrium

A state in a PN junction where the net result is zero current because charge carriers are equal and moving in reverse directions.

Potential Barrier

The potential energy a charged particle must have in order to cross the depletion region of a PN junction.

Diffusion current ($S_I$)

A current flow resulting from the migration of minority carriers across the junction from the n-side to the p-side.

Diffusion

The process where charge particles redistribute by moving from regions of high concentration to regions of low concentration using only thermal motion.

Drift current ($D_I$)

Current due to the movement of majority carriers across the junction, influenced by the application of an electric field.

Forward voltage drop

The small amount of energy needed across terminals to start conduction, which is approximately $0.7\,V$ for silicon.

Shockley equation

The mathematical expression relating diode current ($I_D$) and applied voltage ($V_D$): $I_D = I_0 [ \exp(\frac{qV_D}{nKT}) - 1 ]$.

Reverse saturation current ($I_0$)

A small current that flows in the reverse-biased region, which is a function of doping geometry and temperature.

Thermal Voltage ($V_T$)

A voltage defined as $V_T = \frac{KT}{q}$, which is approximately $25.9\,mV$ at room temperature.

Ideality factor ($n$)

A value between $1$ and $2$ in the Shockley equation that depends on the physical construction of the diode.

Conduction Voltage ($V_C$)

The minimum voltage value beyond zero ($0.2\,V$ for Ge and $0.7\,V$ for Si) at which noticeable current begins to flow through a diode.

Peak Reverse Voltage (PRV)

An alternative term for Peak Inverse Voltage (PIV), representing the maximum reverse bias voltage a rectifier can block.

Avalanche Breakdown

A breakdown process in junctions at reverse-bias voltages above $5\,V$ where minority carriers acquire high kinetic energy and create more carriers through collisions.

Zener Breakdown

A breakdown process occurring at reverse-bias voltages below $5\,V$ where a strong electric field tears electrons out of covalent bonds.

Avalanche Multiplication

The process of breaking covalent bonds on crystal ions to create more mobile carriers, occurring at a knee voltage ($\le -5\,V$).

Diode Breakdown Voltage

The minimum value of the applied reverse biased voltage that makes the diode conduct appreciably in reverse, potentially damaging it.

Knee (Cut-in) Voltage

The specific forward voltage point at which the current through the junction starts to increase rapidly.

Maximum Forward Current

The maximum instantaneous forward current that a PN-junction can withstand without destroying the junction.

Maximum Power Rating

The maximum power that the PN-junction can dissipate without being destroyed.

Rectification

The process of converting an Alternating Current (AC) source into a Direct Current (DC) form.

Half Wave Rectifier

A circuit using a single p-n junction diode in series with a load resistor to allow only half cycles of supply voltage to pass.

Half Wave Rectification

A process where a single diode allows only the positive path of the AC signal to pass and blocks the negative path completely.

Full Wave Rectifiers

Devices that use the full cycle of the input waveform by rectifying both positive and negative half cycles.

Center tapped full wave rectifier

A rectifier circuit using two diodes and a transformer with a common center connection to rectify both half cycles.

Full wave bridge rectifier

A rectifier using four individual diodes in a closed loop configuration to produce a unidirectional output without a center tapped transformer.

Ripple

The cyclic variation in the level of the output voltage due to AC components existing in the DC output from a rectifier.

Filter

A device, typically a capacitor, used to smoothen out pulsations and remove unwanted frequencies from the DC output of a rectifier.

Voltage Doubling

A process using an electronic circuit with diodes and capacitors to achieve exactly twice the input voltage at the output.

Clippers (Limiter)

Diode circuits used to eliminate part of a waveform above or below a predetermined reference level without distorting the remaining part.

Series Clipper

A clipper circuit where the diode is placed in series with the load resistance.

Shunt Clipper

A clipper circuit where the diode is shunted (placed in parallel) across the load resistance.

Positive Diode Clipper

A clipper circuit that specifically removes only the positive half cycles of the input signal.

Negative Diode Clipper

A clipper circuit that specifically removes only the negative half cycles of the input voltage.

Combinational Diode Clipper

Also known as a two-level clipper, it uses both types of biased diode clippers in combination to clip a signal between two levels.

Clampers (Level Shifter)

Circuits used for shifting the entire waveform of an AC signal up or down by adding a DC voltage source; also called a DC restorer.

Light Emitting Diodes (LEDs)

Optical semiconductor devices that convert electrical energy directly into light energy when forward biased.

Photons

The form of energy (light) released when free electrons in the conduction band of an LED recombine with holes in the valence band.

Forbidden (Energy) Gap

The region between the conduction and valence bands; the size of this gap determines the intensity and color of emitted light.

Photodiodes

Semiconductor components that accept light energy as input and change it into an electric current, acting as constant current generators.

PIN Structure

A p-type, intrinsic, and n-type structure used in photodiodes to achieve fast response times in high-speed applications.

Zener Diode

A diode that maintains a fixed voltage level despite variations in source voltage and load current by operating in a controlled breakdown region.

Zener Regulator

A practical application where a Zener diode is operated at its breakdown region to maintain a constant output voltage across a load.