This is the final section of Module 6 in the Navy Basic Electricity and Electronics series, a module on parallel circuits. The sections so far are:
6.1 Rules for Voltage and Current
6.2 Rules for Resistance and Power
6.3 Variational Analysis
This final section is on troubleshooting problems with parallel circuits and is rather short. It consists of five experiments.
1. The first experiment involves voltage and shows that the voltage drop in each parallel branch is the same as the applied voltage at the source.
2. The second experiment has to do with current and shows that the total amperage is the sum of all the branch currents.
3-4. The fourth experiment has to do with a short in one of the branches of a parallel circuit. "Current follows the path of least resistance" (104). Accordingly, if there is a short, then all the current will go through that path. This will blow a fuse if one is in play.
If there is an open in one branch, it effectively disappears from the system. The voltage and resistance in other individual branches stays the same, but the total current will drop (and thus total resistance will go up).
5. A short can cause considerable damage to the other components of a circuit. The ohmmeter function of a multimeter can help locate a short, as there will be no resistance in that branch. (Fire and smoke may also help :-) De-energize circuit before measuring.