Ohm’s Law

Teaching and Learning Resources

Exercise 3: A Series Circuit


  1. 1.Build the circuit as shown. R1 should be a 12 Ohm resistor and R2 should be a 15 Ohm resistor. The supply voltage is 6V.


  1. 2.Using Ohm’s Law, calculate what you would expect the current flowing through the two resistors to be.


  1. 3.Calculate what voltage should be dropped across each resistor.


  1. 4.Measure the current and the voltage dropped across each resistor, is it what you would expect?


5. Challenge: Replace both resistors with two different “unknown” resistors. Using your circuit and some Ohm’s law, work out what the resistance of each resistor must be.