Electrical Circuits 104b

Page 1: Introduction

  • IL.M. Learning Resources for Skilled Trades focusing on Heavy Equipment Technician.

  • Topic: Electrical Circuits in First Period, Electrical I and Electronics (190104b).

Page 2: Copyright Notice

  • © 2022, Northern Alberta Institute of Technology (NAIT) and Southern Alberta Institute of Technology (SAIT).

  • Reproduction of this publication is prohibited without prior written permission from publishers.

  • NAIT and SAIT logos are trademarks and unauthorized use is prohibited.

  • Efforts have been made to ensure the accuracy of the publication.

Page 3: Table of Contents

  1. Objective One

    • Electrical Symbols

    • Electrical Circuit Components

    • Electrical Circuit Conditions

  2. Objective Two

    • Circuit Types

  3. Objective Three

    • Ohm's Law

    • Kirchhoff's Laws

    • Electrical Power

  4. Objective Four

    • Reading Circuit Diagrams

    • The Diagrams

    • The Calculations

    • Applying Ohm's Law to Circuit Diagrams

  5. Objective Five

    • Circuit Failures

    • Circuit Defects

    • Self-Test

    • Self-Test Answers

Page 5: Electrical Circuits Rationale and Outcomes

  • Importance of understanding electrical circuits in heavy equipment and trucks: series, parallel, series-parallel forms.

  • Outcome: Identify circuit types and defects

  • Objectives:

    1. List components of a basic circuit.

    2. Identify circuit types and their properties.

    3. Explain electrical laws and formulas.

    4. Apply laws and formulas to calculate circuit values.

    5. Explain effects of circuit defects on operation.

Page 6: Objective One - Components and Symbols

  • Electrical symbols vary but are crucial for understanding wiring diagrams.

  • Familiarity with common electrical symbols enhances comprehension of schematics.

Page 7: Electrical Circuit Components

  • A complete circuit requires:

    • Power source (e.g., a battery).

    • Load (e.g., a lamp).

    • Conductors (wires).

    • Control (switch).

  • Introduction of overcurrent protection devices (fuses, fusible links, circuit breakers) to prevent excessive current flow.

Page 8: Electrical Circuit Conditions

  • Differences between open and closed circuits:

    • Closed circuit allows current to flow.

    • Open circuit stops current flow, due to broken connections or open switches.

Page 9: Objective Two - Circuit Types

  • Circuit types:

    • Series Circuit: Only one path for current.

    • Parallel Circuit: Multiple paths for current flow.

    • Series-Parallel Circuit: Contains both series and parallel components.

Series Circuit Characteristics

  • One path for current flow.

  • Current is identical at all points.

  • Total resistance equals sum of resistances.

  • Voltage drops sum equal source voltage.

Page 10: Series Circuit with Common Ground

  • Utilizes the equipment's frame as part of the return pathway for current.

  • Enhances circuit simplicity and safety.

Page 11: Parallel Circuits

  • Characteristics:

    • Same voltage across all branches.

    • Total current equals sum of individual branch currents.

    • Adding resistances decreases total resistance.

    • Total equivalent resistance is less than the smallest branch resistance.

Page 12: Series-Parallel Circuits

  • Combines features of series and parallel circuits.

  • Various configurations exist; can interconnect components using series elements within parallel setups.

Page 13: Objective Three - Electrical Laws

  • Ohm's Law: Relates voltage, current, and resistance.

    • Formula: E = I × R (where E = voltage, I = current, R = resistance).

Ohm's Law Relationships

  • Current and voltage relationships:

    • Increased voltage leads to increased current (if resistance constant).

    • Increased resistance leads to decreased current (if voltage constant).

Page 15: Kirchhoff's Laws

  • Current Law: Sum of currents entering a junction equals currents leaving.

  • Voltage Law: In a closed loop, voltage rises equal voltage drops.

Page 17: Electrical Power

  • Power measured in watts (W).

    • Formula: P = E × I (power = voltage × current).

Page 18: Objective Four - Circuit Diagrams

  • Importance of understanding circuit diagrams for diagnosing electrical components.

Page 21: Analyzing Electrical Circuits

  • Break down complex circuits to analyze voltages and currents with Ohm's Law.

  • Understand current flow and voltage drop across resistors in series.

Page 28: Objective Five - Circuit Defects

  • Types of circuit defects:

    1. Open Circuits: Continuity loss due to breaks.

    2. Short-Circuits: Unintended current paths.

    3. Ground Faults: Live wires contacting the ground.

    4. High Resistance: Poor connections causing circuit issues.

Page 36: Consequences of Circuit Defects

Open Circuits

  • Results in no current flow.

Short Circuits

  • Leads to increased current flow and can damage components.

High Resistance Effects

  • Causes reduced current and poor component performance.

Page 42: Self-Test

  • Review multiple-choice questions covering electrical concepts and circuits.

Page 49: Self-Test Answers

  • Answers provided for self-assessment.