5.5 Troubleshooting Series Circuits

This is the fifth and final week of Module 5 in the Navy Basic Electricity and Electronics series. This module is on troubleshooting problems in series circuits. The first four sections were:

5.1 Voltage, Resistance, and Current
5.2 Ohm's Law Formula
5.3 Power
5.4 Internal Resistance

1. Most of the problems that occur in a series circuit either come from a short circuit or an open circuit. A short circuit is where there is a current path that shouldn't exist creating more current than is desirable. An open is where a part of the circuit is not connected or not fully connected and thus the current is not flowing as it should.

There can be a direct short circuit and there can be partial shorts. A direct short circuit is where the poles of the power source are directly connected in some way to each other. This will likely mess up the power source. A partial short only by-passes some of the components.

2. The purpose of a fuse is to keep the components in a circuit from damage in the case of a short. The symbol for a fuse is:

Fuses are rated for the amount of amps that they can safely carry.

You can locate a short using either a voltmeter or an ohmmeter. The voltmeter will tell you if there is too much voltage. Meanwhile, an ohmmeter will read 0 when it shouldn't.

3. An open circuit can also be found either with a voltmeter or an ohmmeter. When an ohmmeter is measured across an open element, it will read infinity. A voltmeter will read nothing across parts of the circuit where the open is not. But it will read full voltage across the open component.

An open circuit often results from a blown fuse or a defective switch.