Electrical Symbols & Electronic Symbols
Electrical symbols and electronic circuit symbols are used for drawing schematic
diagram.
Symbol Component name Meaning
Wire Symbols
Electrical Wire Conductor of electrical current
Connected Wires Connected crossing
Not connected Wires Wires are not connected
Switch Symbols and Relay Symbols
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
Ground Symbols
Used for zero potential reference and electrical shock
Earth Ground
protection.
Chassis Ground Connected to the chassis of the circuit
Digital / Common Ground
Resistor Symbols
Resistor
Resistor reduces the current flow.
Resistor
Potentiometer Adjustable resistor - has 3 terminals.
Potentiometer
Variable Resistor / Rheostat
(IEEE)
Adjustable resistor - has 2 terminals.
Variable Resistor / Rheostat (IEC)
Capacitor Symbols
Capacitor
Capacitor is used to store electric charge. It acts as short
circuit with AC and open circuit with DC.
Capacitor
Polarized Capacitor Electrolytic capacitor
Polarized Capacitor Electrolytic capacitor
Variable Capacitor Adjustable capacitance
Inductor / Coil Symbols
Inductor Coil / solenoid that generates magnetic field
Iron Core Inductor Includes iron
Variable Inductor
Power Supply Symbols
Voltage Source Generates constant voltage
Current Source Generates constant current.
AC Voltage Source AC voltage source
Electrical voltage is generated by mechanical rotation of the
Generator
generator
Battery Cell Generates constant voltage
Battery Generates constant voltage
Generates voltage as a function of voltage or current of other
Controlled Voltage Source
circuit element.
Generates current as a function of voltage or current of other
Controlled Current Source
circuit element.
Meter Symbols
Measures voltage. Has very high resistance. Connected in
Voltmeter
parallel.
Measures electric current. Has near zero resistance.
Ammeter
Connected serially.
Ohmmeter Measures resistance
Wattmeter Measures electric power
Lamp / Light Bulb Symbols
Lamp / light bulb
Lamp / light bulb Generates light when current flows through
Lamp / light bulb
Diode / LED Symbols
Diode Diode allows current flow in one direction only (left to right).
Allows current flow in one direction, but also can flow in the
Zener Diode
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
Transistor Symbols
NPN Bipolar Transistor Allows current flow when high potential at base (middle)
PNP Bipolar Transistor Allows current flow when low potential at base (middle)
Made from 2 bipolar transistors. Has total gain of the product
Darlington Transistor
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
Misc. Symbols
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
Loudspeaker Converts electrical signal to sound waves
Microphone Converts sound waves to electrical signal
Operational Amplifier Amplify input signal
Antenna Symbols
Antenna / aerial
Transmits & receives radio waves
Antenna / aerial
Dipole Antenna Two wires simple antenna
Logic Gates Symbols
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
