Parallel Circuits Lab
How do Parallel Circuits Work?
Purpose:
You will build and analyze parallel circuits.
You will determine how total current and branch currents are related in parallel circuits.
Materials: meter, battery, bulbs & bulb holders
You will build and analyze parallel circuits.
You will determine how total current and branch currents are related in parallel circuits.
Materials: meter, battery, bulbs & bulb holders
Read through the lab and create a data table to hold any measurements or calculations you will complete. **If you have no data tables, you will lose 10 points from the lab**.
Make sure the meter is set up properly for the different measurements you will be taking.
Make sure the meter is set up properly for the different measurements you will be taking.
Procedure: Part 1
- Using two batteries, measure the total voltage that will be used in the circuit. Record.
- Gather two bulbs. Measure the resistance of each bulb. Record.
- Build the circuit in the diagram, but use two bulbs in series instead of only one!
- Measure current in the circuit and record.
- Measure and record the voltage drop across each bulb. Record.
- Calculate resistance for each bulb using Ohm's Law. Record.
Procedure: Part 2
- Using two batteries, measure the total voltage that will be used in the circuit.
- Build the circuit in the diagram.
- Measure current in branch 1. Measure where the "A" is in the diagram. Record.
- Measure current in branch 2. Measure where the "A" is in the diagram. Record.
- Measure and record the voltage drop across each bulb. Record.
- Using Ohm's Law, calculate the resistance in each branch. Record.
Analysis: Answer 2-9 as a text response on Edmodo. (This means type in your answers when you attach your photos.)
- Upload a photo of your data tables from parts 1 & 2 to Edmodo.
- In part 1, look at your measured resistance of each bulb and your calculated resistance of each bulb using Ohm’s Law. What can you state about the measured resistance vs. the calculated resistance?
- In which part did you build a parallel circuit? In which part did you build a series circuit?
- What did you notice about the current between part 1 and part 2?
- What observations can you make about the voltage drops across the bulbs between part 1 and part 2?
- What can you conclude about the voltage drops and the battery voltage in part 2?
- If you had added a third branch with a bulb to part 2, what do you predict would have happened with the current in each branch, the voltage drop across each bulb, and the resistance in each branch?
- Explain what you think is happening to current and voltage as more branches (in part 2) are being added?
- Which of these circuits would you be more likely to use when wiring your house? Explain why.