Measuring Resistance

Resistance is the opposition to passage of an electric current. One ohm is the resistance through which 1 V of electric force causes one ampere to flow. Two common methods for measuring resistance are the 2-wire method and the 4-wire method. For both methods, a current is sent through a resistor with a measurement device measuring the voltage drop from the signal across the resistor. The 2-wire method is easier to implement, but is not as accurate for resistances below 100 Ω. To calculate resistance, use the following formula:

R = V/I

where R = resistance, V = voltage, and I = current.