Active components rely on a source of energy (usually from the
DC circuit, which we have chosen to ignore) and usually can inject
power into a circuit, though this is not part of the definition.
Active components include amplifying components such as
transistors, triode vacuum tubes (valves), and tunnel diodes.
Semiconductors
Diodes
Conduct electricity easily in one direction, among more specific
behaviors.
- Diode, Rectifier, Bridge rectifier
- Schottky diode, hot carrier diode – super fast diode with lower
forward voltage drop
- Zener diode – Passes current in reverse direction to provide a
constant voltage reference
- Transient voltage suppression diode (TVS), Unipolar or Bipolar
– used to absorb high-voltage spikes
- Varactor, Tuning diode, Varicap, Variable capacitance diode – A
diode whose AC capacitance varies according to the DC voltage
applied.
- Light-emitting diode (LED) – A diode that emits light
- LASER diode – A semiconductor laser
- Photodiode – Passes current in proportion to incident
light
-
- Avalanche photodiode Photodiode with internal gain
- Solar Cell, photovoltaic cell, PV array or panel, produces
power from light
- DIAC (Diode for Alternating Current), Trigger Diode, SIDAC) –
Often used to trigger an SCR
- Constant-current diode
- Peltier cooler – A semiconductor heat pump
Transistors
Transistors were considered the invention of the century they
changed electronic circuits forever. The first transistor was a
vacuum tube. A transistor is an electronic switch that, when enough
power goes through it, turns on some other aspect of the circuit.
Active components are used for amplification.
- Bipolar transistors
-
- Bipolar junction transistor (BJT, or simply "transistor") – NPN
or PNP
-
- Photo transistor – Amplified photodetector
- Darlington transistor – NPN or PNP
-
- Photo Darlington – Amplified photodetector
- Sziklai pair (Compound transistor, complementary
Darlington)
- Field-effect transistor (FET)
-
- JFET (Junction Field-Effect Transistor) – N-CHANNEL or
P-CHANNEL
- MOSFET (Metal Oxide Semiconductor FET) – N-CHANNEL or
P-CHANNEL
- MESFET (MEtal Semiconductor FET]])
- HEMT (High electron mobility transistor)
- Thyristors
-
- Silicon-controlled rectifier (SCR) – Passes current only after
triggered by a sufficient control voltage on its gate
- TRIAC (TRIode for Alternating Current) – Bidirectional SCR
- Unijunction transistor (UJT)
- Programmable Unijunction transistor (PUT)
- SIT (Static induction transistor)
- SITh (Static induction thyristor)
- Composite transistors
-
- IGBT (Insulated-gate bipolar transistor)
Integrated circuits
- Digital
- Analog
-
- Hall effect sensor – Senses a magnetic field.
- Current sensor – Senses a current through it.
Optoelectronic devices
- Optoelectronics
-
- Opto-Isolator, Opto-Coupler, Photo-Coupler – Photodiode, BJT,
JFET, SCR, TRIAC, Zero-crossing TRIAC, Open collector IC, CMOS IC,
Solid state relay (SSR)
- Opto switch, Opto interrupter, Optical switch, Optical
interrupter, Photo switch, Photo interrupter
- LED display – Seven-segment display, Sixteen-segment display,
Dot-matrix display
Display technologies
Current:
- Filament lamp (indicator lamp)
- Vacuum fluorescent display (VFD) (preformed characters, 7
segment, starburst)
- Cathode ray tube (CRT) (dot matrix scan (e.g. computer
monitor), radial scan (e.g. radar), arbitrary scan (e.g.
oscilloscope)) (monochrome & colour)
- LCD (preformed characters, dot matrix) (passive, TFT)
(monochrome, colour)
- Neon (individual, 7 segment display)
- LED (individual, 7 segment display, starburst display, dot
matrix)
- Flap indicator (numeric, preprinted messages)
- Plasma display (dot matrix)
Obsolete:
- Filament lamp 7 segment display (aka 'minitron')
- Nixie Tube
- Dekatron (aka glow transfer tube)
- Magic eye tube indicator
- Penetron (a 2 colour see-through CRT)
Vacuum tubes (valves)
Based on current conduction through a vacuum
Amplifying tubes
- Triode
- Tetrode
- Pentode
- Hexode
- Pentagrid
- Octode
- Microwave tubes
-
- Klystron
- Magnetron
- Traveling-wave tube
Optical detectors or emitters
- Phototube or Photodiode – tube equivalent of semiconductor
photodiode
- Photomultiplier tube – Phototube with internal gain
- Cathode ray tube (CRT) or Television picture tube
- Vacuum fluorescent display (VFD) – Modern non-raster sort of
small CRT display
- Magic eye tube – Small CRT display used as a tuning meter
(obsolete)
- X-ray tube – Produces x-rays
Discharge devices
Obsolete:
- Mercury arc rectifier
- Voltage regulator tube
- Nixie tube
- Thyratron
- Ignitron
Power sources
Sources of electrical power:
- Battery – acid- or alkali-based power supply
- Fuel cell – an electrochemical generator
- Power supply – usually a mains hook-up
- Photo voltaic device – generates electricity from light
- Thermo electric generator – generates electricity from
temperature gradients
- Electrical generator – an electromechanical power source.