What to validate using Ohm’s Law

Ohm’s Law can be used to validate the static values of circuit components, current levels, voltage supplies, and voltage drops. If, for example, a test instrument detects a higher than normal current measurement, it could mean that resistance has decreased or that voltage has increased, causing a high-voltage situation. This could indicate a supply or circuit issue.

In direct current (dc) circuits, a lower than normal current measurement could mean that the voltage has decreased, or circuit resistance has increased. Possible causes for increased resistance are poor or loose connections, corrosion and/or damaged components.

Loads within a circuit draw on electrical current. Loads can be any sort of component: small electrical devices, computers, household appliances or a large motor. Most of these components (loads) have a nameplate or informational sticker attached. These nameplates provide safety certification and multiple reference numbers.

Technicians refer to nameplates on components to learn standard voltage and current values. During testing, if technicians find that customary values do not register on their digital multimeters or clamp meters, they can use Ohm's Law to detect what part of a circuit is faltering and from that determine where a problem may lie.