Electrical Symbols & Electronic Symbols
Electrical symbols and electronic circuit symbols are used for drawing schematic diagram.
The symbols represent electrical and electronic components.
Table of Electrical Symbols
Symbol Component name Meaning 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 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) Potentiometer (IEEE) Adjustable resistor - has 3 terminals. Potentiometer (IEC) Variable Resistor / Rheostat (IEEE) Adjustable resistor - has 2 terminals. Variable Resistor / Rheostat (IEC) Trimmer Resistor Preset resistor Thermistor Thermal resistor - change resistance when temperature changes Photoresistor / Light dependent resistor (LDR) Photo-resistor - 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 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 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 Lamp / light bulb Lamp / light bulb Diode Diode allows current flow in one direction only (left to right). 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 Bus Contains several wires. Usually for data / address. Bus Bus 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 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. Multiplexer / Mux 4 to 1 Demultiplexer / Demux 1 to 4 Connects selected output to the input line.