Electrical and electronic wiring symbols

Wire

Conductor of electrical current

Connected wires

Not connected wires

SPST switch

Disconnects current when open

SPDT switch

Selects between two connections

Pushbutton Switch (N.O)

Momentary switch - normally closed

Pushbutton switch (N.C)

Momentary switch - normally closed

DIP switch

is used for onboard configuration

SPST relay

Relay open / close connection by an electromagnet

SPDT relay

Relay open / close connection by an electromagnet

Jumper

Close connection by jumper insertion on pins

Solder bridge

Solder to close connection

Earth ground

Used for zero potential reference and electrical shock protection

Chassis Ground

Connected to the chassis of the circuit

Digital / Common Ground

Resistor

Reduces the current flow - IEEE

Resistor

IEC

Potentiometer

Adjustable resistor - has 3 terminals. IEEE

Potentiometer

Adjustable resistor - has 3 terminals. IEC

Variable resistor / Rheostat

Adjustable resistor - has 2 terminals. IEEE

Variable resistor / Rheostat

Adjustable resistor - has 2 terminals. IEC

Trimmer resistor

Preset resistor

Thermistor

Thermal resistor - change resistance when temperature changes

Photoresistor / light dependent resistor (LDR)

Change resistance with light intensity

Capacitor

Used to store electric charge. Acts as short circuit with AC and open circuit with DC

Capacitor

Used to store electric charge. Acts as short circuit with AC and open circuit with DC

Polarized capacitor

electrolytic capacitor

Polarized capacitor

Electrolytic capacitor

Variable capacitor

Adjustable capacitance

Inductor

Coil / solenoid that generates magnetic field

Iron core inductor

Includes iron

Variable inductor

Voltage source

Generate constant voltage

Current source

Generates constant current

AC voltage source

Generator

Electrical voltage is generated by mechanical rotation of the generator

Battery cell

Generates constant voltage

Battery

Generates constant voltage

Controlled voltage source

Generates voltage as a function of voltage or current of other circuit element.

Controlled current source

Generates current as a function of voltage or current of other circuit element

Voltmeter

Measures voltage. Has very high resistance. Connected in parallel

Ammeter

Measures current. Has near zero resistance. Connected serially

Ohmmeter

Measures resistance

Wattmeter

Measures electric power

Lamp / light bulb

Generates light when current flows through

Lamp / light bulb

Generates light when current flows through

Lamp / light bulb

Generates light when current flows through

Diode

Allow current flow in on direction only - left (anode) to right (cathode)

Zener diode

Allows current flow in one direction, but also can flow in the reverse direction when above breakdown voltage

Schottky diode

Is a diode with low voltage drop

Varactor / varicap diode

Variable capacitance diode

Tunnel diode

Light emitting diode

Emits light when current flows though

Photodiode

Photodiode allows current flow when exposed to light

NPN Bipolar transistor

Allows current flow when low potential at base (middle)

PNP Bipolar transistor

Allows current flow when low potential at base (middle)

Darlington transistor

Made from 2 bipolar transistors. Has total gain of the product of each gain.

JFET-N transistor

N-channel field effect transistor

JFET-P transistor

P-channel field effect transistor

NMOS transistor

N-channel MOSFET transistor

PMOS transistor

P-channel MOSFET transistor

Motor

Electric motor

Transformer

Change AC voltage from high to low or vice versa

Electric bell

Rings when activated

Buzzer

Produces buzzing sound

Fuse

Disconnects when current above threshold. Used to protect circuit from high currents

Fuse

Disconnects when current above threshold. Used to protect circuit from high currents

Bus

Contains several wires. Usually for data address

Bus

Contains several wires. Usually for data address

Bus

Contains several wires. Usually for data address

Optocoupler / opto-isolator

Isolates connection to other board

Loudspeaker

Converts electrical signal to sound waves

Microphone

Converts sound waves to electrical signal

Operational amplifier

Amplify input signal

Schmitt trigger

Operates with hysteresis to reduce noise

Analog to digital converter (ADC)

Converts analog signal to digital numbers

Digital to analog converter (DAC)

Converts digital numbers to analog signal

Crystal oscillator

Used to generate precise frequency clock signal

Antenna

Transmits and receives radio waves

Antenna

Transmits and receives radio waves

Dipole antenna

Two wires simple antenna

Not gate (inverter)

Outputs 1 when input is 0

And gate

Output 1 when both inputs are 1

NAND gate

Outputs 0 when both inputs are 1 (not + and )

Or gate

Output 1 when any input is 1

Nor gate

Output 0 when any input is 1. (Not + or)

XOR gate

Output 1 when inputs are different (exclusive or)

D flip-flop

Stores one bit of data

Multiplexer / mux 2 to 1

Connects the output to selected input line

Multiplexer / mux 4 to 1

Connects the output to selected input line

Demultiplexer / demux 1 to 4

Connects selected output to the input line