Electronic Components, Symbols & Circuit Diagrams
A practical visual guide to common schematic symbols used in electronics, electrical systems and Amateur Radio circuits.
How to use this reference
Search by component name or filter by category. Every card shows the schematic symbol, reference prefix, purpose and a short practical note. Symbol styles can vary slightly between IEC and ANSI standards.
Showing 20 components
Resistor
Limits current, divides voltage and sets circuit operating levels.
Unit: ohm (Ω)Variable Resistor
Provides adjustable resistance for tuning, bias or level control.
Includes potentiometers and rheostatsCapacitor
Stores electric charge; used for filtering, coupling and timing.
Unit: farad (F)Polarized Capacitor
High-capacitance component with defined positive and negative leads.
Observe polarity before connectionInductor
Stores energy magnetically and opposes changes in current.
Unit: henry (H)Transformer
Transfers AC energy between windings for voltage conversion or isolation.
Common in power and RF circuitsDiode
Allows conventional current mainly in one direction.
Terminals: anode and cathodeLight-Emitting Diode
Produces light when forward biased; normally needs a series resistor.
Abbreviation: LEDZener Diode
Operates in reverse breakdown for voltage reference or regulation.
Specified by Zener voltageNPN Transistor
Bipolar transistor used for switching and signal amplification.
Emitter arrow points outwardN-Channel MOSFET
Voltage-controlled transistor for efficient switching and amplification.
Terminals: gate, drain and sourceBattery
Supplies DC electrical energy from one or more electrochemical cells.
Long line indicates positive terminalAC Voltage Source
Represents a source whose voltage changes polarity periodically.
Often shown with a sine waveGround
Defines the circuit’s reference potential or connection to earth.
Ground styles depend on circuit purposeSPST Switch
Opens or closes a single electrical path.
SPST: single-pole, single-throwFuse
Opens a circuit when current exceeds its safe rated value.
Replace only with the specified ratingLamp
Converts electrical energy into visible light.
Also represents an incandescent loadElectric Motor
Converts electrical power into mechanical motion.
Symbol may include AC or DC designationAntenna
Converts radio-frequency electrical signals to or from radio waves.
Used in transmitters and receiversElectrical Meter
Measures quantities such as voltage, current or resistance.
Letter inside identifies the measurementTry another name or select a different category.
Simple LED Indicator Circuit
A battery supplies DC power through a switch and current-limiting resistor to an LED. Each diagram label corresponds to the legend.
Basic diagram conventions
Connected wires
A filled junction dot normally shows that crossing conductors are electrically connected.
Component references
Letters such as R1, C2 and Q3 identify individual components in a schematic and parts list.
Values and ratings
Labels beside a symbol specify values such as 330 Ω, 10 µF, 12 V or maximum power.
Signal direction
Many diagrams are arranged so signals generally travel from left to right and power from top to bottom.
Safety: A schematic explains electrical relationships, not necessarily physical wiring or safe construction. Disconnect power before working on a circuit and obtain qualified assistance for hazardous voltages, transmitters or high-energy systems.