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Electrical & Electronic Symbols

Electrical & Electronic Symbols


Component name


Wire Symbols
 1 Electrical Wire Conductor of electrical current
 2 Connected Wires Connected crossing
 3 Non Connected Wires Wires that cross & are not connected
Switch Symbols and Relay Symbols
 4 SPST Switch Disconnects current when open
 5 SPDT Switch Selects between two connections
 6 Pushbutton Switch (N.O) Momentary switch - Normally Open
 7 Pushbutton Switch (N.C) Momentary switch - Normally Closed
 8 DIP Switch DIP switch is used for on-board configuration
 9 SPST Relay Relay open / close connection by an electromagnet
 10 SPDT Relay
 11 Jumper Close connection by jumper insertion on pins.
 12 Solder Bridge Solder to close connection
Ground Symbols
 13 Earth Ground Used for zero potential reference and electrical shock protection.
 14 Chassis Ground Ground connected to the chassis.
Resistor Symbols
 15 Resistor (IEEE) Resistor reduces the current flow.
 16 Resistor (IEC)
 17 Potentiometer (IEEE) Adjustable resistor - has 3 terminals.
 18 Potentiometer (IEC)
 19 Variable Resistor / Rheostat (IEEE) Adjustable resistor - has 2 terminals.
 20 Variable Resistor / Rheostat (IEC)
 21 Trimmer Resistor Pre-set resistor
 22 Thermistor Thermal resistor - change resistance when temperature changes
 23 Photo Resistor / Light dependent resistor (LDR) Photo Resistor - change resistance with light intensity change
Capacitor Symbols
 24 Capacitor Capacitor is used to store electric charge. It acts as short circuit with AC and open circuit with DC.
 25 Capacitor
 26 Polarized Capacitor Electrolytic capacitor
 27 Polarized Capacitor Electrolytic capacitor
 28 Variable Capacitor Adjustable capacitance
Inductor / Coil Symbols
 29 Inductor Coil / solenoid that generates magnetic field
 30 Iron Core Inductor Includes iron
 31 Variable Inductor  Moving the core farther into the coil increases the permeability, increasing the magnetic field and the inductance.
Power Supply Symbols
 32 Voltage Source Generates constant voltage
 33 Current Source Generates constant current.
 34 AC Voltage Source AC voltage source
35 Generator Electrical voltage is generated by mechanical rotation of the generator
 36 Battery Cell Generates constant voltage
 37 Battery Generates constant voltage
 38 Controlled Voltage Source Generates voltage as a function of voltage or current of other circuit element.
 39 Controlled Current Source Generates current as a function of voltage or current of other circuit element.
Meter Symbols
 40 Voltmeter Measures voltage. Has very high resistance. Connected in parallel.
 41 Ammeter Measures electric current. Has near zero resistance. Connected serially.
 42 Ohmmeter Measures resistance
 43 Wattmeter Measures electric power
Lamp / Light Bulb Symbols
 44 Lamp / light bulb Generates light when current flows through
 45 Lamp / light bulb
 46 Lamp / light bulb
Diode / LED Symbols
 47 Diode Diode allows current flow in one direction only (left to right).
 48 Zener Diode Allows current flow in one direction, but also can flow in the reverse direction when above breakdown voltage
 49 Schottky Diode Schottky diode is a diode with low voltage drop
 50 Varactor / Varicap Diode Variable capacitance diode
 51 Tunnel Diode  A type of semiconductor that is capable of very fast operation, well into the microwave frequency region, made possible by the use of the quantum mechanical effect called tunnelling.
 52 Light Emitting Diode (LED) LED emits light when current flows through
 53 Photodiode Photodiode allows current flow when exposed to light
Transistor Symbols
 54 NPN Bipolar Transistor Allows current flow when high potential at base (middle)
 55 PNP Bipolar Transistor Allows current flow when low potential at base (middle)
 56 Darlington Transistor Made from 2 bipolar transistors. Has total gain of the product of each gain.
 57 JFET-N Transistor N-channel field effect transistor
58 JFET-P Transistor P-channel field effect transistor
 59 NMOS Transistor N-channel MOSFET transistor
 60 PMOS Transistor P-channel MOSFET transistor
Misc. Symbols
 61 Motor Electric motor
 62 Transformer Change AC voltage from high to low or low to high.
 6364 Electric bell Rings when activated
 65 Buzzer Produce buzzing sound
 66 Fuse The fuse disconnects when current above threshold. Used to protect circuit from high currents.
 67 Bus Contains several wires. Usually for data / address.
 68 Bus
 69 Bus
 70 Optocoupler / Opto-isolator Optocoupler isolates connection to other board
 71 Loudspeaker Converts electrical signal to sound waves
 72 Microphone Converts sound waves to electrical signal
 73 Operational Amplifier Amplify input signal
 74 Schmitt Trigger Operates with hysteresis to reduce noise.
 75 Analog-to-digital converter (ADC) Converts analog signal to digital numbers
 76 Digital-to-Analog converter (DAC) Converts digital numbers to analog signal
 77 Crystal Oscillator Used to generate precise frequency clock signal
Antenna Symbols
 78 Antenna / aerial Transmits & receives radio waves
 79 Antenna / aerial
 80 Dipole Antenna Two wires simple antenna
Logic Gates Symbols
 81 NOT Gate (Inverter) Outputs 1 when input is 0
 82 AND Gate Outputs 1 when both inputs are 1.
 83 NAND Gate Outputs 0 when both inputs are 1. (NOT + AND)
 84 OR Gate Outputs 1 when any input is 1.
 85 NOR Gate Outputs 0 when any input is 1. (NOT + OR)
 86 XOR Gate Outputs 1 when inputs are different. (Exclusive OR)
 87 D Flip-Flop Stores one bit of data
 88 Multiplexer / Mux 2 to 1 Connects the output to selected input line.
 89 Multiplexer / Mux 4 to 1
 90 Demultiplexer / Demux 1 to 4 Connects selected output to the input line.


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