What is a "circuit"?

What is a Circuit?

 

Ok, time to get back to work.  Thus far we have discussed voltage and current.  This time we are going to talk about another electrical concept, the “CIRCUIT”. Have you ever heard someone talking about an electrical problem and heard them say, “must have been a short”?? This is the short version (no pun intended) of the phrase, “short circuit”, and it is one of the most used and perhaps mis-used phrases in electricity. In order to understand what a “short” or a short circuit is, we must first understand what a circuit is.

In a previous discussion we talked about current flow. In any electrical system, voltage (the pressure) causes current to flow in a CIRCUIT. In a direct current system, the current flows in only one direction, while in an Alternating Current system, the current flows in both directions. The current flows in a CIRCUIT.

What is a circuit? It is the complete path through which electrical current flows.

In a simple direct current (DC) circuit, such as a battery, a switch, and a light, the current leaves the battery, flows through wire to the switch, through more wire to the lamp, then through more wire back to the battery, a complete circuit.

An alternating current (AC) circuit works in a similar manner except the electrons which make up the current flow in the circuit, move back and forth in the circuit, moving first in one direction, then reversing and moving in the other direction. As far as the operation of the circuit goes, it is the same in that there is a beginning, and end, and no interruptions between.

In our simple circuit example above, the current (either DC or AC) flowed through all the components of the circuit, the battery, the wire, the switch, and the lamp. In a short circuit, the electrical current does not pass through one or more of the components of the circuit. Normally this will cause problems in the operation of the circuit.