Simple Circuits Lab
Pick a circuit layout, set the battery voltage, and flip the switch to watch bulbs light up. Compare series and parallel arrangements and find out what a resistor really does to the current.
Guided Experiment: Series vs Parallel Bulbs
If you compare two bulbs wired in series with the same two bulbs wired in parallel at the same battery voltage, which arrangement do you predict will be brighter and why?
Write your hypothesis in the Lab Report panel, then click Next.
Circuit View
Current flowing: 600 mA
Readings
Per-Bulb Readings
Data Table
(0 rows)| # | Trial | Layout | Battery(V) | Total I(mA) | Bulb 1(V) | Bulb 2(V) | Lit? |
|---|
Reference Guide
Ohm's Law
Ohm's Law connects three quantities in a circuit. Voltage is the push from the battery, current is the flow of charge, and resistance is how hard the circuit is to push current through.
Doubling the voltage doubles the current, and doubling the resistance halves it. That single rule explains every reading you see in this lab.
Series Circuits
In a series circuit the components are connected end to end, like beads on a string. The same current flows through every part, and the resistances add together.
Two bulbs in series share the battery voltage, so each one is dimmer than a single bulb on the same battery. If one bulb burns out, the whole loop goes dark.
Parallel Circuits
In a parallel circuit each component has its own path back to the battery. Every branch gets the full battery voltage, so each bulb stays as bright as it would alone.
The total current is the sum of the branch currents, which is why a parallel pair pulls four times as much current as a series pair at the same voltage.
Power and Brightness
A bulb's brightness depends on the electrical power it turns into light and heat. Power equals voltage times current, so more voltage or more current both make a bulb shine brighter.
Adding a resistor in series with a bulb raises the total resistance, lowers the current, and shrinks the power, so the bulb visibly dims.
