Electrical symbols

Electrical Wire

Conductor of electrical current

Connected Wires

Connected crossing

Not Connected Wires

Wires are not connected

SPST Toggle Switch

Disconnects current when open

SPDT Toggle Switch

Selects between two connections

Pushbutton Switch (N.O)

Momentary switch - normally open

Pushbutton Switch (N.C)

Momentary switch - normally closed

DIP Switch

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 (IEEE)

Resistor reduces the current flow.

Resistor (IEC)

Resistor reduces the current flow.

Potentiometer (IEEE)

Adjustable resistor - has 3 terminals.

Potentiometer (IEC)

Variable Resistor / Rheostat (IEEE)

Adjustable resistor - has 2 terminals.

Variable Resistor / Rheostat (IEC)

Adjustable resistor - has 2 terminals.

Trimmer Resistor

Preset resistor

Thermistor

change resistance when temperature changes

Photo-resistor / Light dependent resistor (LDR)

- change resistance with light intensity change

Capacitor

Capacitor is used to store electric charge. It acts as short circuit with AC and open circuit with DC.

Capacitor

Capacitor is used to store electric charge. It 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

Generates constant voltage

Current Source

Generates constant current.

AC Voltage Source

AC voltage source

Generator

Electrical voltage is generated by mechanical rotation of the generator

Battery Cell

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 electric current. Has near zero resistance. Connected serially.

Ohmmeter

Measures resistance

Wattmeter

Measures electric power

Lamp / light bulb

Generates light when current flows through

Diode

Diode allows current flow in one 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

Schottky diode is a diode with low voltage drop

Varactor / Varicap Diode

Variable capacitance diode

Tunnel Diode

Light Emitting Diode (LED)

LED emits light when current flows through

Photodiode

Photodiode allows current flow when exposed to light

NPN Bipolar Transistor

Allows current flow when high 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 low to high.

Electric bell

Rings when activated

Buzzer

Produce buzzing sound

Fuse

The fuse disconnects when current above threshold. Used to protect circuit from high currents.

Fuse

The 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

Optocoupler 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 / aerial

Transmits & receives radio waves

Antenna / aerial

Transmits & receives radio waves

Dipole Antenna

Two wires simple antenna

NOT Gate (Inverter)

Outputs 1 when input is 0

AND Gate

Outputs 1 when both inputs are 1.

NAND Gate

Outputs 0 when both inputs are 1. (NOT + AND)

OR Gate

Outputs 1 when any input is 1.

NOR Gate

Outputs 0 when any input is 1. (NOT + OR)

XOR Gate

Outputs 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.

Diode

Diode allows current flow in one 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

chottky diode is a diode with low voltage drop

Varactor / Varicap Diode

Variable capacitance diode

Tunnel Diode

semiconductor that is capable of very fast operation, well into the microwave frequency region,

Light Emitting Diode (LED)

LED emits light when current flows through

Photodiode

Photodiode allows current flow when exposed to light

NPN Bipolar Transistor

Allows current flow when high 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