Brightness of Light Bulbs in Series and Parallel Circuits // HSC Physics

📖 Visit our website: www.scienceready.com.au
🏅 Become a Patron: / scienceready
🎶 Follow our Tiktok / hscscienceready
♥️ Follow our Instagram page: / hscscienceready
👍🏼 Like our Facebook page: / hscscienceready
⌚Timestamp
00:00 Review of Electric Power
01:11 Brightness in Series Circuit
04:44 Brightness in Parallel Circuit
08:50 Summary
📚Syllabus
• investigate quantitatively the application of the law of conservation of energy to the heating effects of electric currents, including the application of 𝑃 = 𝑉𝐼 and variations of this involving Ohm’s Law (ACSPH043)

[@AndrewWeng]

This work is the goat for my advanced Y9 science class. Thank you. I'm in Queensland btw, but your work is the world's best in my view and should be used everywhere. Science channels not even half as good as yours have over 1 million subscribers.

[@roberthuntley1090]

If you are talking about traditional incandescent light bulbs, they approximate to constant current devices over a wide voltage range. As the voltage rises, the filament warms up, increases its resistance and so brings the current down to something close to the original value. Any voltage between the first visible glow of the filament to full brightness will do. The only caveat is that it takes a second or so for the filament to change temperature, so there is a slight delay.
There used to old-school bodges based on that effect; before modern constant current techniques were available. Back in the 70s, I used to charge a small 6 volt motorcycle battery from a 12 volt car charger at a current suitable for its low capacity. Also, I can vaguely remember a hi--fi amplifier using that method when a constant current was needed .