Ohm’s Law

Voltage equals current multiplied by resistance. It helps calculate expected current or find extra resistance. It is a basic tool for electrical diagnosis. For example, a corroded ground connection adds resistance, so less current reaches a headlight and it shines dimmer. Voltage drop tests apply Ohm's law in practice to find such resistance.

Higher resistance lowers current at the same voltage.

Corroded connections add resistance. Measure under load for realistic results.