======Series and Parallel Circuits======


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**Alternative titles:** Current and Voltage in Bulb Circuits
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====Summary====                   
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====Procedure====  
  - Build a simple series circuit with one bulb and a battery. Insert an ammeter in series with the loop and a voltmeter across the bulb.
  - Switch on the circuit, observe the brightness of the bulb, and record current (A) and potential difference (V).
  - Add a second bulb in series. Note brightness of both bulbs and record new current and voltage values for each bulb.
  - Extend to circuits with three or four bulbs in series, recording brightness, current, and potential difference.
  - Construct parallel circuits: connect two bulbs, each on its own branch, across the battery. Place an ammeter in each branch and a voltmeter across each bulb.
  - Repeat with three and then four bulbs, each on separate parallel branches. Record brightness, current in each branch, and voltage across each bulb.
  - Compare results in a table showing brightness, current, and potential difference for each bulb across all circuit types.



====Links==== 
Electric Circuits: Series and Parallel - funsciencedemos
: 
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Series & Parallel Circuits - Patrick Haney: 
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📄 Investigating bulb brightness experiment - BBC Bitesize: [[https://www.bbc.co.uk/bitesize/guides/zsk4msg/revision/4]]\\


====Variations====
  * Use bulbs of different wattage ratings to compare brightness in mixed series and parallel circuits.
  * Replace one branch of the parallel circuit with two bulbs in series, and compare with a single bulb on another branch.
  * Try repeating with LEDs (with suitable resistors) instead of filament bulbs.



====Safety Precautions====
  * Use a low-voltage supply (e.g., cells or a lab power supply set to a safe voltage).
  * Switch off between readings to prevent bulbs from overheating.
  * Place equipment on a heatproof mat to avoid scorching surfaces.
  * Do not exceed the recommended supply voltage for the bulbs to avoid breakage.
  * Handle bulbs carefully to prevent injury from broken glass if a bulb fails.




====Questions to Consider====
  * Why do bulbs get dimmer when more are added in series? (Because the supply voltage is shared between bulbs, so each receives less potential difference.)
  * Why do bulbs in parallel remain as bright as a single bulb? (Each branch receives the full supply voltage, so each bulb operates at its normal brightness.)
  * How does current behave in a series circuit? (The same current flows through every component in series.)
  * How does current behave in a parallel circuit? (Branch currents add together to equal the total current from the supply.)
  * If three identical bulbs are connected in parallel, what happens to the total current compared with one bulb? (It roughly triples, because each branch draws the same current as a single bulb.)