Resistance is measured using analog or digital multimeters. These tools also measure current, voltage, and more for various applications. Why measure resistance? To determine the condition of a circuit or component. The higher the resistance, the lower the current flow, and vice versa. In general, the resistance of components used to control circuits (such as switches and relay contacts) starts out very low and increases over time due to factors such as wear and dirt. Loads such as motors and solenoids...