2.1: Basic Electrical Circuits
- Page ID
- 3266
Describe basic circuit concepts
You must understand how basic circuits function to properly diagnose and repair electrical problems. Now that you understand a simple circuit and how the basic components are connected, you can assemble more complex circuits and observe their characteristics.
A circuit must provide a complete path for current flow from the power source. The current must flow through a control device into an electrical load and back to the power source through a wire or through a vehicle chassis.
In equipment, wire is normally used only on the insulated side of the circuit, since the return circuit is the chassis. Some components may require a ground wire from the component to the frame This type of circuit is called the single wire system (Figure 1).

- Single wire circuit
Figure \(\PageIndex{1}\): (CC BY-NC-SA; BC Industry Training Authority) - Two wire circuit
There are three types of basic electrical circuits:
- series circuits
- parallel circuits
- series-parallel (combination) circuits