How do you use Ohm's Law in Series circuits?
Purpose:
You will determine how to calculate total resistance in a series circuit.
You will build a circuit with a dimmer switch.
Materials:
Batteries, resistors, meter, wires, bulb and bulb holder, potentiometer
You will determine how to calculate total resistance in a series circuit.
You will build a circuit with a dimmer switch.
Materials:
Batteries, resistors, meter, wires, bulb and bulb holder, potentiometer
NOTE: Create a data table before beginning.
Procedure:
Procedure:
- Measure voltage of the battery. Record. Measure the resistance of the R1 resistor. Record.
- Build a circuit using the R1 resistor. Measure the current through the circuit. Record the value.
- Measure the resistance of the R2 resistor. Record.
- Add the R2 resistor to your circuit. (Your circuit should now have two resistors.)
- Measure the current though the circuit. Record the value.
- Measure the resistance of the R3 resistor. Record.
- Add the R3 resistor to your circuit.
- Measure the current though the circuit. Record the value.
- Using Ohm's Law calculate the total resistance in each circuit, using the battery voltage and the current for each circuit.
- Build a new circuit with a bulb, potentiometer, and battery.
- Using the dimmer switch, turn the bulb until the light is very dim.
- Record approximate brightness.
- Measure voltage across the bulb. Record.
- Measure current through the circuit. Record.
- Make the bulb a little brighter and repeat steps 12-14. Continue for a total of FIVE settings of the potentiometer.
- Use Ohm's Law to calculate the total resistance for each setting of the potentiometer.
Analysis: (Complete in notebook and upload photos to Edmodo when done.)
- Graph bulb resistance (y) vs. current (x) for each potentiometer setting. Label your axes and title your graph.
- What happens to bulb resistance when current is higher?
- How could you use series circuits when building your electric house next week?
- At higher temperatures, the tungsten atoms in the light bulb filament move around more. Propose an explanation for why resistance of tungsten increases with temperature.