Active / Semiconductor

Diode

A diode with a very low forward voltage drop and fast switching speed, made from a metal-semiconductor junction instead of a p-n junction.

Diode

A diode designed to conduct in REVERSE at a precise breakdown voltage, holding that voltage steady. Used as a simple voltage reference or clamp.

Diode

A diode built to die for your circuit: normally invisible, it clamps voltage spikes (ESD, inductive kicks, surges) by avalanching in nanoseconds and dumping the energy as heat.

Diode

A full-wave rectifier that converts AC to DC using four diodes arranged in a bridge configuration. Provides a more efficient conversion than a single diode half-wave rectifier.

Diode

The 'special devices' chapter of EDC in one place: diodes engineered for jobs other than rectifying — voltage-variable capacitance (varactor), negative resistance (tunnel, Gunn) and RF switching/attenuation (PIN).

Transistor

A current-controlled switch and amplifier with three pins. A small base current controls a much larger collector current. The classic transistor.

Transistor

A junction FET: a normally-ON transistor whose channel is pinched off by reverse-biasing the gate. Prized for very high input impedance and low noise in analog front-ends.

Transistor

A hybrid power switch: MOSFET-style voltage-driven gate with a BJT-style low-loss conduction path. The workhorse for switching hundreds of volts at tens/hundreds of amps — motor drives, welders, induction cooktops.

Transistor

Two BJTs stacked so the first amplifies the second's base current: gains of 1,000–30,000 from one package. Lets a weak signal switch amps — at the cost of a ~1 V minimum drop.

Transistor

A three-terminal negative-resistance device that snaps on when its emitter voltage crosses a fixed fraction of the supply — the textbook relaxation oscillator and the classic trigger for SCRs. Obsolete in industry, immortal in exams.

Thyristor

A three-terminal semiconductor device that acts as an electronic switch for alternating current (AC), capable of controlling power in both directions.

Thyristor

A two-terminal trigger device that blocks until about ±32 V, then avalanches and dumps a sharp pulse — used almost exclusively to fire triacs cleanly and symmetrically in dimmers.

IC (Analog)

A high-gain differential amplifier building block. With feedback it does amplification, filtering, comparison and math on analog signals. Hugely versatile.

IC (Analog)

A high-gain amplifier that compares two voltages and outputs a digital signal indicating which is higher. Acts as a decision-making circuit.

Integrated Circuit

A power amplifier on a chip: signal in, speaker out, minimal external parts. From the venerable LM386 breadboard companion to Class-D chips that drive real watts off a battery without a heatsink.

IC (Power)

An integrated circuit that efficiently converts voltage levels using switching elements and inductors, either stepping down (buck) or stepping up (boost) input voltage.

IC (Power)

An integrated circuit that amplifies low-power control signals to drive high-current motors, enabling direction and speed control from microcontrollers like Arduino.

IC (Digital)

Digital building blocks that perform Boolean logic (AND, OR, NOT, NAND, NOR, XOR, XNOR) on one or more binary inputs. The 74xx TTL and 4000 CMOS families contain hundreds of pre-built gate ICs.

IC (Digital)

Chips that remember. EEPROM keeps small settings without power, Flash holds big code/data, RAM is fast scratch space that forgets at power-off. Endurance and interface are the gotchas.

IC (Compute)

A tiny computer on a chip: CPU, memory and I/O pins in one package. You program it to read sensors, drive outputs and run the logic of a product.

Optoelectronic

An LED and a phototransistor sealed in one package, coupling signals by light. Provides galvanic isolation between two circuits so high-voltage and low-voltage sides never share a current path.

Optoelectronic

Light in, current out. A photodiode produces a tiny current proportional to light — fast and linear. A phototransistor adds gain: more signal, slower and less linear. The receiving half of every IR link.

Optoelectronic

A display device shaped like a '8' that shows numbers by lighting up individual segments. Common in digital clocks, calculators, and meters.

Optoelectronic

A display technology that uses liquid crystals (LCD) or organic light-emitting diodes (OLED) to present visual information. Common in smartphones, monitors, and embedded systems.

Optoelectronic

A large-area photodiode run in forward power-producing mode: light directly generates electricity. One silicon cell gives ~0.5–0.6 V regardless of size — area sets the current.

Optoelectronics

An LED pushed past threshold into stimulated emission: coherent, focused light from a chip. Powers fiber-optic links, laser pointers, engravers, LiDAR and the optical-communication unit of the ECE syllabus.