# Intro to Circuits 120

This class describes the basic components of an electrical circuit and explains how they are represented in schematic drawings. Includes an Interactive Lab.

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## Class Details

Class Name:
Intro to Circuits 120
Description:
This class describes the basic components of an electrical circuit and explains how they are represented in schematic drawings. Includes an Interactive Lab.
Version:
1.0
Difficulty:
Beginner
Number of Lessons:
19
Spanish
Related 2.0 Class:
Introduction to Circuits 201

## Class Outline

• Objectives
• What Is a Circuit?
• Components of a Circuit
• Drawings and Abbreviations
• Source
• Path
• Resistance
• Control
• Protective Devices
• Grounding
• Chassis Ground
• Fuses
• Circuit Breakers
• Kirchhoff’s Laws
• Series Circuits
• Parallel Circuits
• Combination Circuits
• Summary

## Objectives

• Understand the importance of a conductor.
• Identify the components in a basic circuit.
• Describe how schematic drawings use symbols to represent the parts of a circuit.
• Describe the purpose of the source in an electrical circuit.
• Describe the purpose of the path in an electrical circuit.
• Define resistance.
• Describe how a switch controls the flow of electrical current.
• Describe the purpose of the load in an electrical circuit.
• Identify the two basic types of circuit protective devices.
• Explain the purpose of a grounding conductor in an electrical circuit.
• Define a chassis ground.
• Explain how fuses operate.
• Explain how common circuit breakers work.
• Describe the main concept of Kirchhoff’s Laws.
• Describe a series circuit.
• Describe a parallel circuit.
• Describe a combination circuit.

## Certifications

SME
• CMfgT
MSSC
• MSSC Maintenance Awareness

## Glossary

Vocabulary Term Definition
alternating current Current that regularly reverses the direction of its flow.
amp Unit of measure for the strength of an electrical current.
atom The smallest particle of an element that still retains its characteristics.
bimetallic strip Two metals with different expansion temperatures that are fused together. When heated or cooled, one strip pulls on the other and curls.
bus bar A grounded metal bar in a breaker box to which all neutral and grounding wires are connected.
chassis The frame of a machine, such as a car or clothes washer.
chassis ground A wire that runs from the motor to the machine's frame.
circuit A controlled path for electricity. A circuit includes a source, path, load, and control.
circuit breaker A safety device that detects too much current in a circuit. A circuit breaker often contains a bimetallic strip that bends and trips a switch that opens a circuit.
combination circuit A route for the flow of electricity that has elements of both series and parallel circuits.
conductor A material or element that allows free movement of electrons and therefore allows easy flow of electricity. Most conductors are metals.
contact A connection between two conductors that allows electricity to flow.
control A component in a circuit that controls the flow of electricity.
current The flow of electricity. Current is measured in amps.
electrical box The system that serves as the source for household or building electricity. The electrical box is where the main electrical service comes in and is distributed throughout the building.
electricity A form of energy created by the movement of electrons.
electron A negatively charged particle that orbits the nucleus of an atom. Electrons are involved in bonding and electrical conductivity.
filament A thin wire that becomes hot and bright when electricity passes through it. Used in most light bulbs.
fuse A safety device that detects too much current in a circuit. A fuse often has a component that melts and opens the circuit.
grounded Safely connected to a neutral body, like the earth, which can absorb a stray electrical charge.
grounded conductor Another name for the neutral wire in an electrical circuit.
grounding circuit A system that diverts stray current to a neutral source via the neutral (white) wire.
grounding conductor The extra wire in an electrical system that provides a low-resistance path to ground for stray current. The grounding conductor is usually bare copper or covered with green insulation.
hot wire An electrically charged, conductive wire that provides power to the load. The hot wire is usually covered with black insulation.
insulator A material such as rubber or glass that does not readily conduct electricity.
Kirchhoffs Law Two laws that describe the flow of current in an electrical circuit. Put simply, they imply that what goes in must come out.
load The component in a circuit that converts electricity into light, heat, or mechanical motion. Examples of loads are a light bulb, appliance, or machine.
neutral wire The wire that conducts the power back to the source and completes the circuit. The neutral wire is usually covered with white insulation.
overcurrent device A component like a breaker or a fuse that protects circuits from too much current flow.
parallel circuit A route for the flow of electricity that has multiple paths.
path A conductor that directs electricity in a circuit. The path is often copper wire.
protective device A component like a fuse, breaker, or grounding circuit that prevents damage to an electrical system.
resistance The opposition to current flow. Resistance is measured in ohms.
schematic drawing A graphical representation of an electrical system.
series circuit A route for the flow of electricity that has only one path.
source The device that provides electrical power to a circuit. The source is the origin of electricity, such as a power plant.
valence shell The outermost orbit of electrons in an atom.
voltage A measure of electrical pressure or potential. Voltage is measured in volts.
voltage drop A drop in voltage along a conductor through which electricity is flowing. Occurs after electricity passes through a load.
wiring diagram A detailed plan for an electrical system.