Industrial and Power Electronics: Diodes, Rectifiers, and Thyristors

Practice vocabulary flashcards covering power electronics, rectifier topologies, diode operations, and thyristor devices such as SCRs, DIACs, and TRIACs.

Industrial Electronics

A specialized field of electronics that focuses on the design, application, and maintenance of electronic systems and devices used in industrial environments for automation, control, monitoring, and conversion.

Power Electronics

A branch of electrical engineering that deals with the conversion, control, and conditioning of electrical power using semiconductor devices and circuit topologies.

Power Electronics Converters

Circuits that convert electrical power from one form to another using semiconductor switches, enabling efficient control of voltage, current, frequency, and power.

Linear Power Supply

A power supply type that uses a transformer and a linear regulator to provide stable and regulated power.

Switch Mode Power Supply

A type of power supply that uses high-frequency switching semiconductor devices to convert and regulate electrical power.

Power Diode

A robust semiconductor diode designed to handle high-voltage, high-current, and high-power applications compared to standard low-power diodes.

Forward Bias

The condition where the positive terminal of a voltage source is connected to the anode of a diode and the negative terminal to the cathode; conduction begins once reaching the threshold voltage ($0.7\,\text{V}$ for silicon, $0.3\,\text{V}$ for germanium).

Reverse Bias

The condition where the anode of a diode is connected to the negative side of the power supply and the cathode to the positive side, causing the diode to act as an open switch with high resistance and only a minimal leakage current in nanoamperes.

Rectifier

An electrical device or circuit that converts alternating current (AC) into direct current (DC).

Uncontrolled Rectifier

A rectifier circuit that uses ordinary diodes which conduct automatically when forward-biased, offering no control over the output voltage or power once built.

Controlled Rectifier

A rectifier circuit that uses thyristors (SCRs) instead of ordinary diodes, allowing output voltage, current, and power to be regulated by adjusting the firing angle.

Half-Wave Rectifier

A rectifier circuit that transforms only one half-cycle of alternating current (AC) into direct current (DC).

Full-Wave Rectifier

A rectifier that converts both positive and negative half-cycles of AC into DC, providing double the output voltage compared to a half-wave rectifier.

Bridge Rectifier

A circuit arrangement of four diodes in a bridge (diamond) pattern used to achieve full-wave AC to DC rectification.

Single-Phase Bridge Rectifier

A rectifier consisting of four diodes in a bridge configuration that converts single-phase AC input into a pulsating DC output, typically used in low- to medium-power applications.

Three-Phase Voltage

An AC electrical system that uses three separate voltage waveforms, each shifted by $120^\circ$ from the others.

Three-Phase Rectification

The process of converting a balanced 3-phase AC power supply into a smooth, stable DC supply using solid-state diodes or thyristors, significantly reducing ripple voltage compared to single-phase rectifiers.

Average DC Voltage ($V_{\text{DC}}$) of a 3-Phase Half-Wave Rectifier

The output voltage calculated using the peak phase voltage ($V_{\text{P}}$) or RMS phase voltage ($V_{\text{RMS}}$), given by $V_{\text{DC}} = \frac{3\sqrt{3}}{2\pi} \times V_{\text{P}} \approx 0.827 \times V_{\text{P}} = 1.17 \times V_{\text{RMS}}$.

Thyristor

The family name for a class of four-layer (PNPN) semiconductor switching devices used for power control.

Silicon Controlled Rectifier (SCR)

A four-layer (PNPN) semiconductor device with three terminals—Anode (A), Cathode (K), and Gate (G)—that conducts current only from anode to cathode when triggered by a gate current pulse.

Latching

The operating behavior where an SCR, once triggered into conduction by a gate current pulse, remains fully ON like a closed switch even after the gate current is completely removed.

Natural Commutation

A method of turning off an SCR in an AC circuit where the current naturally falls to zero at the AC zero-crossing point.

Forced Commutation

A turn-off method used in DC circuits where an external circuit, typically containing capacitors and inductors, forces the SCR current to zero or briefly reverses it.

DIAC (Diode for Alternating Current)

A two-terminal, bidirectional semiconductor device without a gate terminal that initiates conduction only when the applied voltage reaches its breakover voltage.

Breakover Voltage (DIAC)

The specific threshold voltage, typically $30\text{--}40\,\text{V}$, at which a DIAC switches from an OFF state into conduction and enters its negative resistance region.

TRIAC (Triode for Alternating Current)

A three-terminal semiconductor device used for controlling AC power, functionally equivalent to two inverse-parallel SCRs sharing a common gate terminal.

Full-Wave Control (TRIAC)

A switching mode where the TRIAC gates ON during each half-cycle of AC and automatically unlatches at the end of each half-cycle when the instantaneous supply voltage and current drop to zero.