KM-09-KT01: Principles and Functions of Schematic Diagrams

3.1 Lesson Outcomes

After completing this lesson, learners will be able to:

• Explain the principles and functions of circuits
• Identify symbols associated with schematic diagrams
• Explain codes, tags, and labels used in schematic diagrams
• Describe the fundamentals of drawing schematic diagrams
• Explain circuit operating sequences and component interactions
• Read and interpret schematic diagrams correctly
• Apply work procedures and housekeeping practices when handling schematic diagrams
• Identify symbols and abbreviations used within RPAS schematic systems

3.2 Overview

This lesson introduces learners to schematic diagrams used within RPAS systems and aviation environments. Learners will explore circuit principles, schematic symbols, diagram interpretation, circuit functions, and the role of schematic diagrams in supporting RPAS operations, maintenance, troubleshooting, and system understanding.

3.3 Main Lesson Content

KT0101: Principles, Types and Functions of Circuits

A circuit is a complete electrical path that allows electrical current to flow.

Functions of Circuits

Circuits help:

• Power electronic systems
• Transfer electrical energy
• Control electrical devices
• Support communication systems

Types of Circuits

Series Circuits

Series circuits:

• Have a single path for current flow
• Connect components one after another

If one component fails, the entire circuit stops functioning.

Parallel Circuits

Parallel circuits:

• Have multiple current paths
• Allow independent operation of components

Parallel circuits improve reliability because one failed component does not stop the entire circuit.

Combination Circuits

Combination circuits use:

• Both series and parallel configurations

Circuit Components

Common circuit components include:

• Resistors
• Switches
• Capacitors
• Batteries
• Relays
• Diodes
• Motors

Importance of Circuits in RPAS

RPAS systems use circuits for:

• Flight control systems
• Navigation systems
• Communication systems
• Power distribution

Understanding circuit operation is essential for troubleshooting and maintenance.

KT0102: Symbols Associated with Schematic Diagrams

Schematic diagrams use symbols to represent electrical components.

Purpose of Symbols

Symbols help:

• Simplify circuit drawings
• Improve diagram readability
• Standardize electrical diagrams

Common Schematic Symbols

Resistor Symbol

Represents resistance within a circuit.

Battery Symbol

Represents an electrical power source.

Switch Symbol

Represents devices used to open or close a circuit.

Ground Symbol

Represents the reference point within electrical systems.

Capacitor Symbol

Represents energy storage components.

Diode Symbol

Represents components that allow current flow in one direction.

Importance of Standard Symbols

Standard symbols:

• Improve communication between technicians
• Reduce confusion
• Support accurate troubleshooting

Technicians must correctly identify symbols when interpreting RPAS schematic diagrams.

KT0103: Codes, Tags and Labels

Schematic diagrams use codes, tags, and labels to identify components and connections.

Codes

Codes identify:

• Circuit sections
• System types
• Electrical functions

Tags

Tags help identify:

• Components
• Equipment
• Connection points

Labels

Labels provide:

• Additional information
• Component names
• Voltage ratings
• Wiring details

Importance of Codes and Labels

Codes and labels help:

• Simplify troubleshooting
• Improve maintenance
• Support system identification

RPAS System Identification

RPAS diagrams may include:

• Motor identification labels
• GPS system codes
• Power supply labels
• Communication system identifiers

Proper identification improves maintenance accuracy and operational efficiency.

KT0104: Fundamentals of Drawing a Schematic Diagram

Schematic diagrams visually represent electrical systems and circuit connections.

Purpose of Schematic Diagrams

Schematic diagrams help:

• Explain system operation
• Support troubleshooting
• Assist maintenance
• Improve communication between technicians

Diagram Layout

A good schematic diagram should:

• Be clear and organized
• Use standard symbols
• Include labels and codes
• Show circuit flow correctly

Drawing Principles

When drawing schematic diagrams:

• Components must be correctly positioned
• Connections must be accurate
• Circuit paths must be easy to follow

Circuit Operating Sequence

Circuit diagrams help explain:

• The order of operations
• Component interactions
• System functionality

Interpretation of Schematic Diagrams

Technicians should:

• Read symbols correctly
• Follow current flow
• Understand component relationships
• Interpret labels and tags accurately

Housekeeping and Storage

Schematic diagrams should:

• Be stored safely
• Remain clean and readable
• Be protected from damage

Importance within RPAS

RPAS technicians use schematic diagrams to:

• Diagnose faults
• Repair systems
• Understand aircraft systems
• Maintain operational reliability

3.5 Key Notes / Summary

• Circuits allow electrical current to flow through systems
• Series, parallel, and combination circuits support different functions
• Schematic symbols represent electrical components
• Codes, tags, and labels identify circuit elements
• Schematic diagrams simplify electrical system understanding
• Standard symbols improve communication and troubleshooting
• RPAS systems rely heavily on schematic diagrams for maintenance and diagnostics
• Proper storage and housekeeping protect schematic documentation