Common Symbols in Electrical Circuit Diagrams

Study Notes

Common Symbols in Electrical Circuit Diagrams

Resistor Symbols

Standard Resistor: A zigzag line or rectangle.
Variable Resistor: A zigzag line with an arrow across it.
Fixed Resistor: A rectangle with leads extending from each side.

Inductor Symbols

Standard Inductor: A coiled line or series of loops.
Variable Inductor: A coiled line with a dashed line or an arrow indicating variability.

Ground Symbols

Earth Ground: Three horizontal lines, the top line shorter than the bottom.
Chassis Ground: A series of lines that descend in size, often depicted with a triangle.

Capacitor Symbols

Standard Capacitor: Two parallel lines (plates) with a gap between them.
Polarized Capacitor: Similar to a standard capacitor but one plate is curved to indicate polarity.

Battery Symbols

Single Cell Battery: A series of alternating long and short lines (long line positive, short line negative).
Multiple Cells Battery: Multiple sets of the single cell symbol placed in series.

Resistor Symbols

Standard Resistor: Represented as a zigzag line or rectangle, indicating a component that resists electric current.
Variable Resistor: Depicted as a zigzag line with an arrow, allowing for adjustable resistance in a circuit.
Fixed Resistor: Illustrated as a rectangle with leads extending from either side, signifying a resistor with constant resistance.

Inductor Symbols

Standard Inductor: Shown as a coiled line or a series of loops, symbolizing a component that stores energy in a magnetic field when electrical current flows through it.
Variable Inductor: Illustrated with a coiled line and either a dashed line or an arrow, indicating the ability to change inductance.

Ground Symbols

Earth Ground: Represented with three horizontal lines, where the top line is shorter than the bottom, indicating a reference point in the electrical circuit for safety and stability.
Chassis Ground: Depicted as a series of descending lines, often in a triangular shape, denoting a common ground reference for the metal enclosure of a device.

Capacitor Symbols

Standard Capacitor: Illustrated as two parallel lines (plates) separated by a gap, representing a device that stores electrical energy in an electric field.
Polarized Capacitor: Similar to a standard capacitor but with one curved plate to indicate the correct polarity for connection.

Battery Symbols

Single Cell Battery: Visualized as alternating long and short lines, with the long line representing the positive terminal and the short line the negative terminal.
Multiple Cells Battery: Consists of multiple sets of the single cell symbol connected in series, indicating the cumulative voltage output from several cells linked together.

Resistor Symbols

Standard Resistor: Represented by a zigzag line or rectangle, indicating resistance in the circuit.
Variable Resistor: Displays a similar shape to a standard resistor but includes an arrow which indicates it can be adjusted.
Fixed Resistor: Often shown as a rectangular box, indicating a constant resistance value.
Mismatched Resistor: Appears with a dotted line or special notation, used to indicate a specific functionality or type.

Diode Symbols

Standard Diode: Illustrated by a triangle pointing to a line, representing the direction of current flow from anode to cathode.
Zener Diode: Same as a standard diode but adds a bent line at the cathode, indicating its function in voltage regulation.
Light Emitting Diode (LED): Depicted as a standard diode symbol with two arrows pointing outward, representing emitted light.

Power Source Symbols

Battery: Illustrated by a series of long and short parallel lines, each representing a cell in the battery.
Single Cell: Represented by one pair of long and short lines, indicating a single electrochemical cell.
DC Power Supply: Shown as a circle with plus (+) and minus (-) signs, denoting direct current with specific polarity.
AC Power Supply: Represented by a sine wave symbol or a circle containing a wave, illustrating alternating current.

Transistor Symbols

NPN Transistor: Illustrated as a circle with three leads, with the arrow pointing outward from the emitter, indicating current flow direction.
PNP Transistor: Similar to the NPN but the arrow points inward toward the emitter, signifying a different current flow direction.
Field-Effect Transistor (FET): Depicted with variations based on gate types, typically includes representations of gate, drain, and source connections.

Capacitor Symbols

Standard Capacitor: Shown as two parallel lines (plates) with a space in between, indicating energy storage. One line may be curved for polarized capacitors.
Electrolytic Capacitor: Similar to the standard symbol, but marked with a plus sign on one plate to show polarity.
Variable Capacitor: Similar to a standard capacitor but includes an adjustment mechanism, often represented with a line or gap beside the plates.

Description

Test your knowledge of common symbols used in electrical circuit diagrams, including resistors, inductors, capacitors, ground, and battery symbols. This quiz will help you identify and differentiate these essential components used in circuit design.