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An electronic symbol is a pictogram used to represent various electrical and electronic devices or functions, such as wires, batteries, resistors, and transistors, in a schematic diagram of an electrical or electronic circuit. These symbols are largely standardized internationally today, but may vary from country to country, or engineering discipline, based on traditional conventions.

Standards for symbols
The graphic symbols used for electrical components in circuit diagrams are covered by national and international standards, in particular: • IEC 60617:2025 (also known as BS 3939) - current international standard for electronic symbols. • IEEE 315-1975 (also known as ANSI Y32.2-1975 or CSA Z99-1975) - reaffirmed in 1993, inactivated without replacement as of November 7, 2019. • IEEE 91/91a - graphic symbols for logic functions (used in digital electronics). It is referenced in IEEE 315 / ANSI Y32.2. • Australian Standard AS 1102 (based on a slightly modified version of IEC 60617) - withdrawn without replacement with a recommendation to use IEC 60617. • DIN 40700 and 40900 (Germany) - inactivated. • JIC JIC (Joint Industrial Council) symbols as approved and adopted by the NMTBA (National Machine Tool Builders Association). They have been extracted from the Appendix of the NMTBA Specification EGPl-1967. • IEC 61131-3:2025 for ladder-logic symbols. The standards do not all agree, and use of unusual (even if standardized) symbols can lead to confusion and errors. Symbols usage is sometimes idiosyncratic to engineering disciplines, and national or local variations to international standards exist. For example, lighting and power symbols used as part of architectural drawings may be different from symbols for devices used in electronics. ==Common electronic symbols==
Common electronic symbols
Symbols shown are typical examples, not a complete list. Traces s.''' The CAD symbol for insulated crossing wires is the same as the older, non-CAD symbol for non-insulated crossing wires. To avoid confusion, the wire "jump" (semi-circle) symbol for insulated wires in non-CAD schematics is recommended (as opposed to using the CAD-style symbol for no connection), so as to avoid confusion with the original, older style symbol, which means the exact opposite. The newer, recommended style for 4-way wire connections in both CAD and non-CAD schematics is to stagger the joining wires into T-junctions. The large dot signifies an electrical connection. Grounds The shorthand for ground is GND. Optionally, the triangle in the middle symbol may be filled in. File:IEEE 315 Transmission Path Symbols (75).svg|General ground (IECstyle) File:IEEE 315 Transmission Path Symbols (80).svg|Signal/low-noise ground (the asterisk is not part of the symbol) File:IEEE 315 Transmission Path Symbols (78).svg|Chassis/Earth ground (IECstyle) Sources Voltage text should be placed next to each battery symbol too, such as "3V". File:IEEE 315 Fundamental Items Symbols (90).svg|Battery, single-cell File:IEEE 315 Fundamental Items Symbols (92).svg|Battery, multi-cell File:IEEE 315-1975 (1993) 8.7.3.svg|Solar (photovoltaic) cell File:Voltage source 2.svg|DC voltage source File:Controlled Current source.svg|Controlled DC voltage source File:Current source.svg|Current source File:Controlled Current source 2.svg|Controlled current source File:AC voltage source.svg|AC voltage source Resistors It is very common for potentiometer and rheostat symbols to be used for many types of variable resistors and trimmers. File:Resistor, Rheostat (variable resistor), and Potentiometer symbols.svg|ANSIstyle: (a) Resistor, (b) Rheostat, (c) Potentiometer / Trimmer File:IEC resistors.svg|IECstyle: (a) Resistor, (b) Rheostat, (c) Potentiometer / Trimmer File:IEEE 315-1975 (1993) 2.1.13.svg|Photoresistor (ANSI) File:IEEE 315-1975 (1993) 2.1.12.1.2.svg| File:IEEE 315-1975 (1993) 2.1.6.a.svg|Varistor (ANSI) Capacitors File:IEEE 315 Fundamental Items Symbols (32).svg|Capacitor(IEC 60617 style) File:IEEE 315 Fundamental Items Symbols (35).svg|Polarized capacitor(IEC 60617 style) File:IEEE 315 Fundamental Items Symbols (36).svg|Polarized capacitor (old alternate IEEE 315 style) File:IEEE 315 Fundamental Items Symbols (38).svg|Variable capacitor(IEC 60617 style) File:IEEE 315 Fundamental Items Symbols (41).svg|Ganged (comoving) variable capacitors(IEC style) File:Trimmer capacitor symbol GOST.svg|Trimmer variable capacitor Diodes Optionally, the triangle in these symbols may be filled in, or a line may be drawn through the triangle (less desirable). The words anode and cathode are not part of the diode symbols. For instructional purposes, sometimes one or two letters (A/C or A/K) are placed next to diode symbols similar to how the letters C/B/E or D/G/S are placed next to transistor symbols. "K" is often used instead of "C", because the origin of the word cathode is kathodos, and to avoid confusion with "C" for capacitors in silkscreen of printed circuit boards. Voltage text should be placed next to each zener and TVS diode symbol too, such as "5.1V". File:Diode symbol.svg | Diode (rectifier) File:Schottky diode symbol.svg | Schottky diode File:Zener diode symbol-2.svg | Zener diode File:TVS diode symbols.svg | TVS (Transient Voltage Suppression) diode. Top is unidirectional, bottom is bidirectional. File:LED symbol.svg | LED (Light Emitting Diode) File:Photodiode symbol.svg | Photodiode File:Tunnel diode symbol.svg | Tunnel diode File:Varicap symbol.svg | Varicap File:Shockley diode.svg | Shockley diode File:SCR symbol.svg | SCR (Silicon Controlled Rectifier) File:Diac-schematic-symbol.png | Diac (may be a varistor in older schematics) File:Constant Regulating Diode.png | Constant-current diode File:Symbol Opto-Isulator.svg | Opto-isolator: internal LED (left) and photo transistor (right) Bridge rectifiers There are many ways to draw a single-phase bridge rectifier symbol. Some simplified symbols do not show the internal diodes. File:Bridge Rectifier.svg|Bridge rectifier File:УГО диодного моста.svg|Bridge rectifier File:4 diodes bridge rectifier.jpg|Bridge rectifier File:Bridge Rectifier for single-phase alternating current (symbolic diagram).png|Bridge rectifier File:3 fase bridge rectifier.jpg|Three-phase bridge rectifier Inductors An inductor can be drawn either as a series of loops, or series of half-circles. File:Coil illustration.svg|Inductor symbol (series of loops) File:IEC Inductor.svg|Air-core inductor (IECstyle) File:IEC Inductor with magnetic core.svg|Magnetic-core inductor (IEEEstyle) File:IEC Tapped inductor.svg|Tapped inductor (IECstyle) File:Ferrite bead ring.svg|Ferrite bead (IEEEstyle) File:Reguleeritav pool.jpg|Variable inductor File:Seadepool.jpg|Trimmer variable inductor Transformers Voltage text should be placed on both sides of power transformers, such as 120V (input side) and 6.3V (output side). File:Transformer Iron Core.svg|Transformer File:Transformer center tap.svg|Transformer with center tap on secondary winding (right side) File:Transformer two secondary windings.svg|Transformer with two secondary windings (right side) File:Basic Current Transformer Symbol.svg|Current transformer File:Zero Sequence Current Transformer Symbol.svg|Zero-sequence current transformer (ZSCT) (also known as a window-type current transformer) File:Bushing Type Current Transformer Symbol.svg|Bushing-type current transformer File:Voltage Transformer.svg|Voltage transformer Transistors Optionally, transistor symbols may include a circle. Note: The pin letters B/C/E and G/D/S aren't part of the transistor symbols. Bipolar File:IEEE 315-1975 (1993) 8.6.2.svg|NPN bipolar junction transistor (BJT) File:IEEE 315-1975 (1993) 8.6.1.svg|PNP bipolar junction transistor (BJT) File:IEEE 315-1975 (1993) 8.6.17.svg|NPN Darlington transistor File:PNP darlington.svg|PNP Darlington transistor File:PhototransistorSymbol.png|NPN Phototransistor Unipolar File:IEEE 315-1975 (1993) 8.6.10.1.b.svg|N-channel junction gate field-effect transistor (JFET) File:IEEE 315-1975 (1993) 8.6.11.1.b.svg|P-channel junction gate field-effect transistor (JFET) File:IGFET N-Ch Enh Labelled simplified.svg|Metal–oxide–semiconductor field-effect transistor (MOSFET) File:Enh N channel Mosfet.svg|Enhancement mode, Nchannel MOSFET File:Enh P channel Mosfet 2.svg|Enhancement mode, Pchannel MOSFET Vacuum tubes File:Dioda symbol.svg|Vacuum tube diode File:Trioda symbol.svg|Vacuum tube triode File:Vacuum Tube Tetrode.svg|Vacuum tube tetrode(pin letters not part of symbol) File:Pentoda symbol.svg|Vacuum tube pentode Switches For multiple pole switches, a dotted or dashed line can be included to indicate two or more switch at the same time (see DPST and DPDT examples below). File:Poussoir-NO-symbol.png|Pushbutton, normally open, push-to-make (horizontal line on top) File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (57).svg|Pushbutton, normally open, push-to-make (IEEE-style) File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (58).svg|Pushbutton, normally closed, push-to-break (IEEE-style) File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (59).svg|Pushbutton, normally closed, two circuits (IEEE-style) File:SPST-Switch.svg|Switch, 1P1T, SPST (single-pole single-throw) File:DPST-symbol.svg|Switch, 2P1T, DPST (double-pole single-throw) File:SPDT-Switch.svg|Switch, 1P2T, SPDT (single-pole double-throw) File:DPDT-symbol.svg|Switch, 2P2T, DPDT (double-pole double-throw) File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (85).svg|Slide switch, 1P3T,break-before-make, nonshorting style File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (87).svg|Slide switch, 1P4T,break-before-make, nonshorting style File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (89).svg|Slide switch, 1P4T,make-before-break, shorting style File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (84).svg|Rotary switch, 1P3T,break-before-make, nonshorting style File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (86).svg|Rotary switch, 1P4T,break-before-make, nonshorting style File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (88).svg|Rotary switch, 1P4T,make-before-break, shorting style File:Reed switch symbol.svg|Reed switch, normally open Relays Relays symbols are a combination of an inductor symbol and switch symbol. Note: The pin letters in these symbols aren't part of the standard relay symbol. File:Relay symbols.svg|SPST, SPDT, DPST, DPDT relays (Americanstyle) File:Relay-IEC.svg|SPDT relay (IECstyle) Lamps LED is located in the diode section. File:Neon lamp schematics.svg|Neon lamp File:Indicating lamp.svg|Indicating lamp (IEEEstyle) File:Lamp symbol, old.svg|Incandescent lamp File:Lamp symbol.svg|Indicatory incandescent light bulb File:Light bulb 3.svg|Light bulb Current limiters File:Fuces.svg|Fuse: (b) IEC, (a,c) IEEE/ANSI 315-1975 File:Molded Case Circuit Breaker.svg|Molded-case circuit breaker (MCCB) Voltage limiters TVS and Zener diodes are located in the diode section. File:Symbol Surge Arrester.svg|Gas-discharge tubes (GDT) for ESD discharge File:Symbol Spark gap.svg|Spark gap for ESD discharge Electro-acoustic devices Speaker symbols sometimes include an internal inductor symbol. Impedance text should be placed next to each speaker symbol, such as "8 ohms". File:IEEE Loudspeaker.svg|Loudspeaker(IEEE-style) File:Buzzer-IEC-Symbol.svg|Buzzer(IEC-style) File:IEEE MIC.svg|Microphone(IEEE-style) File:IEC MIC.svg|Microphone(IEC-style) Antennas File:IEEE 315 Fundamental Items Symbols (55).svg|General antenna(IEC-style) File:IEEE 315 Fundamental Items Symbols (58).svg|Dipole antenna(IEC-style) File:IEEE 315 Fundamental Items Symbols (61).svg|Loop antenna(IEC-style) File:IEEE 315 Fundamental Items Symbols (60).svg|Loop antenna(IEEE-style) Cables File:IEEE 315 Transmission Path Symbols (26).svg|Cable, Shielded 1 conductor File:IEEE 315 Transmission Path Symbols (30).svg|Cable, 2 conductor File:IEEE 315 Transmission Path Symbols (29).svg|Cable, Shielded 2 conductor with shield connected to ground File:IEEE 315 Transmission Path Symbols (31).svg|Cable, 5 conductor File:IEEE 315 Transmission Path Symbols (27).svg|Cable, Shielded 5 conductor Connectors There are numerous connector symbol variations. File:Phone Jack Symbols.svg | Phone connectors. "A" is TS, "B" is TRS, "D" is TRS with two switches. File:UEXTPINS.svg | 5x2 shrouded header with notch key and pin names for Olimex UEXT. File:DE-9.svg | DE-9 D-subminiature with host side pin names for RS-232 serial port. ICs Logic gates For the symbols below: A and B are inputs, Q is output. Note: These letters are not part of the symbols. There are variations of these logic gate symbols. Depending on the IC, the two-input gates below may have: 1) two or more inputs; 2) infrequently some have a second inverted output too. File:Buffer ANSI Labelled.svg|Buffer File:NOT ANSI Labelled.svg|Inverter (NOT) File:AND ANSI Labelled.svg|AND File:NAND ANSI Labelled.svg|NAND File:OR ANSI Labelled.svg|OR File:NOR ANSI Labelled.svg|NOR File:XOR ANSI Labelled.svg|XOR File:XNOR ANSI Labelled.svg|XNOR The above logic symbols may have additional I/O variations too: 1) schmitt trigger inputs, 2) tri-state outputs, 3) open-collector or open-drain outputs (not shown). File:Schmitt trigger symbol.svg|Buffer gate with schmitt trigger input File:Tristate buffer.svg|Buffer gate with tri-state output control.(B is the tri-state control) Flip-flops For the symbols below: Q is output, is inverted output, E is enable input, internal triangle shape is clock input, S is Set, R is Reset (some datasheets use clear (CLR) instead of reset along the bottom). There are variations of these flip-flop symbols. Depending on the IC, a flip-flop may have: 1) one or both outputs (Q only, only, both Q & ); 2) one or both forced inputs along top & bottom (R only, S only, both R & S); 3) some inputs may be inverted. File:Inverted SR Flip-flop.svg|Simple SR flip-flop (inverted S & R inputs) File:Gated SR flip-flop Symbol.svg|Gated SR flip-flop File:Transparent Latch Symbol.svg|Gated D flip-flop (Transparent Latch) File:D-Type Flip-flop.svg|Clocked D flip-flop(Set & Reset inputs) File:JK Flip-flop (Simple) Symbol.svg|Clocked JK flip-flop File:T-Type Flip-flop.svg|Clocked T flip-flop OpAmps Note: The outside text isn't part of these symbols. File:Op-amp symbol.svg|Operational amplifier (opamp) File:Comparator symbol.svg|Comparator Voltage Regulator Note: 3pin linear or LDO voltage regulator symbols typically have three words inside their symbols, such as "In" on left side, "Out" on right side", "Gnd" on bottom (for fixed output parts, such as LM7805) or "Adj" on bottom (for adjustable output parts, such as LM317). File:Voltage-Regulator-IEC-Symbol.svg|3-pin Linear or LDO voltage regulator File:LM7805 with Decoupling Capacitor.svg|Example schematic of3-pin voltage regulator Oscillators Frequency text should be placed next to each oscillator symbol, such as "16MHz". File:IEEE 315 Fundamental Items Symbols (113).svg|Crystal oscillator (IEEEstyle) File:Schaltsymbol-Keramikresonator.svg|Ceramic resonator (3 pins) Miscellaneous devices File:Common Hall Sensor Symbol.png|Hall-effect sensor ==Historical electronic symbols==
Historical electronic symbols
The shape of some electronic symbols have changed over time. The following historical electronic symbols can be found in old electronic books / magazines / schematics, and now considered obsolete. Capacitors (historical) All of the following are obsolete capacitor symbols. File:Polarized capacitor symbol 5.png|Obsolete capacitor (very old style) File:Capacitor old.svg|Obsolete capacitor File:Capacitor old with polarity.svg|Obsolete capacitor File:Polarized capacitor symbol 3.svg|Obsolete capacitor File:Elco's.jpg|Obsolete capacitor ==See also==
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