How to understand electrical diagrams

Written by kim lewis
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Electrical diagrams are drawings used to represent circuits. Circuits are electrical components connected to each other by conductors such as wires and solder. These components manipulate and control currents in various ways. Either AC or DC voltage sources may power circuits.

All electrical diagrams follow certain rules. Electrical components are represented by symbols. To understand an electrical diagram, you must know what these symbols represent, the purpose of the various components and how they are placed in a circuit.

Skill level:
Moderately Challenging

Things you need

  • An electrical diagram
  • An introductory physics or electricity text
  • A handbook or data sheets on electrical components

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  1. 1

    Identify the symbols for electrical components that are found in most circuits. These include resistors, capacitors, inductors, transistors, op-amps, and diodes.

  2. 2

    Study the rules that are used to wire these components together. Connections between components are denoted by straight lines. Points on the circuit that are connected by the same wire are at the same potential and are electrically equivalent.

  3. 3

    Learn the rules for connecting components in series or parallel. For example, resistors that are in series behave differently than capacitors that are in series. Resistors that are in series will combine to form a total that increases the resistance in a circuit. However, capacitors in series combine in a way that actually decreases the capacitance in a circuit.

  4. 4

    Identify the symbols for voltage sources such as power supplies and batteries. AC sources are symbolised differently than DC sources. A battery is a DC voltage source with two terminals, where one is positive and the other is negative. It is polarised, which means that the way it is placed into a diagram is important.

  5. 5

    Recognise the difference between polarised and non-polarised components. For example, some capacitors are polarised, while others are not. Resistors are not polarised.

  6. 6

    Study basic circuit combinations. Certain electrical components that are always built and wired the same way function as mini-circuits. They are used to perform certain tasks for a larger circuit, and may be viewed as building blocks. Examples are voltage dividers, diode clamps, and filters. Once you have mastered the basic circuits, then you may proceed to more advanced ones such as logic circuits.

Tips and warnings

  • To learn to read electrical diagrams of simple circuits, you may wish to purchase educational electronics kits. They are inexpensive, and typically include data sheets on the components used, as well as schematics for the project you are to build. They provide a detailed explanation of how the circuit works.
  • After you are comfortable with educational kits, you may then purchase educational project labs or electrical trainers. These may also cover digital and advanced analogue circuits.
  • Always exercise caution when building electrical circuits to avoid burning yourself or damaging your equipment.

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