Basic Circuit Analysis and Troubleshooting

Troubleshooting is the systematic process of recognizing the symptoms of a problem, identifying the possible cause, and locating the failed component or conductor in the circuit. To be proficient at troubleshooting, the technician must understand how the circuit operates and know how to properly use the test equipment. There are many ways in which a system can fail and to cover all of the possibilities is beyond the scope of this text. However, there are some basic concepts that will enable the technician to handle many of the common faults encountered in the electronics.

Before starting a discussion on basic circuits and troubleshooting, the following definitions are given.

• Short circuit—an unintentional low resistance path between two components in a circuit or between a component/conductor and ground. It usually creates high current flow, which will burn out or cause damage to the circuit conductor or components.
• Open circuit—a circuit that is not a complete or continuous path. An open circuit represents an infinitely large resistance. Switches are common devices used to open and close a circuit. Sometimes a circuit will open due to a component failure, such as a light bulb or a burned out resistor.
• Continuity—the state of being continuous, uninterrupted or connected together; the opposite of a circuit that is not broken or does not have an open.
• Discontinuity—the opposite of continuity, indicating that a circuit is broken or not continuous.