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 |
 | 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 |
Ground Symbols | ||
 | Earth Ground | Used for zero potential reference and electrical shock protection. |
 | Chassis Ground | Connected to the chassis of the circuit |
 | Digital / Common Ground | |
Resistor Symbols | ||
 | 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) | |
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 |
 | 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. |
Meter Symbols | ||
 | 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 Symbols | ||
 | Lamp / light bulb | Generates light when current flows through |
 | Lamp / light bulb | |
 | Lamp / light bulb | |
Diode / LED Symbols | ||
 | 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 |
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) |
 | 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 |
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 | |
 | Bus | Contains several wires. Usually for data / address. |
 | Bus | |
 | Bus | |
 | Optocoupler / Opto-isolator | Optocoupler isolates onnection 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 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 |
 | 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. |
