Automotive Electronics Practice Test

If an accessory is spliced into an existing circuit in parallel, what is the effect on the current?

1. The current increases in the circuit

2. The current decreases in the circuit

3. The voltage drops in the circuit

4. The resistance of the circuit increases

The correct answer is: The current increases in the circuit

When an accessory is spliced into an existing circuit in parallel, the overall current in the circuit increases. This happens because parallel circuits offer multiple paths for current to flow. When an additional accessory is connected, it creates another path that allows more current to travel beyond what was flowing in the original circuit. In a parallel configuration, the total current flowing from the power source is the sum of the currents through each path. Therefore, when you add an accessory in parallel, the total current supplied by the source rises in accordance with Ohm's Law (I = V/R), where the resistance decreases as new pathways are provided. The voltage across the circuit remains steady, as each branch of the parallel circuit experiences the same voltage. Hence, the correct answer reflects that the current will indeed increase in the circuit due to the added load.