6.1 Rules for Voltage and Current

So we move on to Module 5 in the Navy Basic Electricity and Electronics series (here is the previous module). This module is on Parallel Circuits (as opposed to the series circuits of the previous module). The first section is "Rules for Voltage and Current."

Some take-aways from this first section:

• A parallel circuit is one which has more than one path for current to follow, although with only one common source.
• Each path provides a "load" with a certain resistance.
• Christmas lights used to be in a series configuration. If one light burned out, the rest wouldn't work. Most now are configured in parallel.
• The voltage across the branches of a parallel circuit will be the same in every branch. Voltage is not additive.
• This is different than in series circuits. For them, we had Kirchhoff's Law--"The sum of the voltage drops equals the applied voltage." Voltage is additive.
• On the other hand, the current--the amount of electrons passing a given point at a given time--is divided up among each branch. Branch current in each branch is determined by the amount of resistance in that branch. The total current equals the total current of all the branches.
• Kirchhoff's Current Law is that the total current is the sum of the current in all the branches.