Electrical symbols and electronic circuit symbols are used for drawing schematic diagram.
The symbols represent electrical and electronic components.
| 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) | ||
| 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 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 (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 | |
| 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 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 | |
| ⎓ | Direct current | Direct current is generated from constant voltage level |
| 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. | |