RW BTEC PRINCIPLES Name ……………………………………………………………………………………………………… Calculating resistance Build a circuit that contains a switch, a small variable resistor and a bulb. Draw your circuit below: Take readings from your ammeter and voltmeter and write them down. Calculate the resistance using Ohm’s Law. (Resistance = Voltage ÷ Current) Change the amount of resistance in the circuit and write down the values of voltage and current. Calculate the resistance. Repeat this once more. Measured Voltage Units are……… Measured Current Units are………. Calculated Resistance Units are………….. RW BTEC PRINCIPLES Name ……………………………………………………………………………………………………… Predicting the current or voltage if given the other two. Use Ohm’s Law to calculate the missing value. Remember: Voltage = Current × Resistance Resistance = Voltage ÷ Current Current = Voltage ÷ Resistance Current (Units………..) Voltage (Units………) 5 100 60 12 3 3 10 15 5000 800 Resistance (Units………..) 20 50