This page is an alphabetical list of electronics components with their common circuit symbols. The headings with links lead to more detailed tutorial documents on those components. The unlinked headings are of very simple devices that are included only to illustrate their circuit symbols.
The descriptive documents will often refer to a component as either a passive or an active device. Passive components, such as resistors and capacitors, are generally two-terminal devices that have no external power source. Active devices, such as transistors, have more than two terminals and have are externally powered so that the device output can be amplified compared to an input. Capacitors
Diodes
Fuses
Note: the SB in the example means "slow blow" Ground or earth
Note: multiple ground symbols in a circuit imply that they are connected to a common ground. Lamps
Inductors
Meters
Note: The voltmeter is used in parallel to measure the potential difference between two points and the ammeter is used in series to measure the current through a point. Operational Amplifiers (op-amps)
Note: The power supply leads, V+ and V- , are often left out of circuit diagrams. Oscillators (quartz crystal)
Power Supplies Battery or dc power source
ac power sources
Resistors
Silicon-controlled rectifier (SCR)
Switches
Transformers
Transistors bipolar
B = base, C = collector, and E = emitter
JFET MOSFET D = drain and S = source
Note: transistor terminals are usually not labeled in circuit diagrams.
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