Identify the resistor value in ohms
Determine the current flowing through the resistor in amperes
Use Ohm’s law: voltage drop = current × resistance
Multiply the current by the resistor value
Express the result in volts
If the resistor is part of a series circuit, use the same current through that resistor
If the resistor is part of a parallel circuit, use the branch current through that resistor
Check units to ensure ohms and amperes are used correctly
Verify the calculated voltage drop does not exceed the source voltage in the circuit