IV Characteristics of Resistors, Filament Lamps, Diodes and LEDs - A Level Physics

[@ordinarykaycee]

I've been struggling with Diodes for a while but as soon as you described it as a "one way valve" it all clicked, especially as a biology student. Thank you for speaking my language

[@PhysicsOnline]

Thanks for you comment. It's early days still but I aim to grow, keep sharing the videos. Hope they're useful.

[@yencheng979]

Thanks so much for all of your videos - they're extremely helpful! :) Keep up the great work!

[@drspinz955]

you need more subscriber. At this quality,you deserve at least 1 million subs!

[@davivvd1994980]

Good explanation, thank you so much!

[@beyondconfuzzled]

thank you sooo much! i was really struggling with diodes, and im still a bit confused about the threshold voltage. is the resistance of the diode still very high until the threshold voltage is reached/exceeded?

[@Abbas.786]

I've seen exam questions with the V and I axis reversed (voltage along the Y-axis and current along the X-axis); do you just rotate the shape of the curve in those cases?

[@ALevelPhysicsOnlineYear13]

+Abbas11227 That's right, your flip it along the diagonal.

[@saimakhankhan2517]

How? i dont get it. how would you flip it exactly?

[@johnmccozner9298]

Reflect in on the x=y line. Just the same shape but reversed direction. Imagine holding it to a mirror

[@saimakhankhan2517]

But the line is on the x=y line. its like on the mirror.

[@saimakhankhan2517]

Actually the line isnt flipped its just rotated in a way that the graph has a negative gradient. i have a picture of it in my book that i didnt see at first,

[@matteo5399]

3:12 Could you please explain why the bottom line suggest a higher resistance?

[@jawadzahid24]

R=V/I, for higher resistance you'll get lower value for current, hence Resistance increases. idk how to put it :'D

[@grassytramtracks]

It's because R=V/I and the axes are the other way round and that means that the resistance is the reciprocal of the gradient, not the gradient

[@willsonbasyal7883]

great!!1 i wonder if you have videos covering all of GCE- As level physics!1

[@PhysicsOnline]

+Willson Basyal Yes I do: www.alevelphysicsonline.com/#!videos/c1p3t

[@oneinabillion654]

Thanks for the vid man

[@barrylee7394]

Thank you so much!

[@zohaib.m]

Amazing. Is this made for the new OCR A syllabus. I would be highly greatful if you could make videos on most of the topics. Liked and shared will all friends. :)

[@PhysicsOnline]

There are videos for pretty much all of the AS OCR physics spec A course. Have a look on my website for the full list.

[@PhysicsOnline]

+A Level Physics Online www.alevelphysicsonline.com/#!videos/c1p3t

[@nosir1479]

5:00 I'm assuming you mean the electrons knock into the tungsten metal lattice.

[@abdurrasheedsadiq7549]

The filament bulb only changes its resistance when it heats up. If the temperature within it was constant, wouldn't it just be another ohmic conductor?

[@PhysicsOnline]

AbdurRasheed Sadiq That's right.

[@kryoomi]

For the Diode graph isn't there a breakdown voltage when current is reversed?

[@PhysicsOnline]

+Crazy Noomi Yes there is. Basically with a really high voltage you can force a current to go the 'wrong' way through a diode but this isn't normally asked about at A Level. There is more info, and a graph, here: en.wikipedia.org/wiki/Breakdown_voltage

[@ribs2635]

good video

[@endover422]

How would the IV characteristic look for the LDR?

[@Elitea20]

endover same as thermistor

[@malmsburycemeterytrust7219]

I hate to disagree - 'cos these videos are so brilliant. But - the lamp does obey ohms law. ie - the current drawn by the lamp is equal to the voltage divided by the resistance of the filament. The difference between the lamp and a resistor is that the resistance of the filament changes as it heats up. So if you apply a voltage to the lamp, the current will change over time as it heats up. You could plot resistance against time - which would change, albeit rapidly over (say) a few milliseconds. The resistance of the lamp once the temperature has settled can be measured on your I V graph as the gradient of the line at a point - ie the tangent to the curve.

[@meltansz5693]

Hi I'm an Edexceler from Bahrain and each time I try to access your Yr.13 videos it says "this video is not available in your country." I don't know if this is a youtube glitch or the video actually hasn't been made open to international students, so could you please help me out with that? It would be greatly appreciated!!

[@PhysicsOnline]

+Mel tansz It's a KZbin issue I'm afraid. There are various countries that don't allow paid content at this time and although I've made it available to all the international countries I can I'm afraid Bahrain isn't available at this time. Sorry.

[@maximusekon146]

what does polarity mean?

[@geoffphillips8183]

I never understand why y axis is I ,current, & x axis is V. Voltage. If it were the other way around... we would see clearly resistance increasing & the gradient would be R if graph were Ohmic. It would be less confusing. Am I right? Thanks 😊

[@timmc1979]

You are controlling the voltage across the component, hence it is on the x axis

[@suhail1200]

Hmm resistance increases and current increases?I thought voltage increases as resistance increases or am I wrong?

[@lisablyumin8291]

This is relevant when it is an ohmic conductor, however a filament lamp is not ohmic and so the resistance is not directly proportional to the voltage (Basically R=V/I does not apply), because ohm's law only applies at a constant temperature

[@lisablyumin8291]

But with a filament lamp the temperature is always increasing

[@Sibasish07]

suhail1200 No ur correct! If u cannot follow the V=IR then why is he telling that to calculate the resistance we need to use V/I...! I have checked other videos this concept is wrong in this video

[@suhail1200]

Sibasish Mukherjee well my exam is done and dusted now so it's kinda late hahaha. Im still not sure to be honest.

[@Sibasish07]

suhail1200 oh nice.. hope it went good

[@sulaymaankhan4525]

Great video, however i dont understand why resistance increases with current for the filament lamp?

[@nickprice2000]

As the current increases, the filament heats up. This means the e- in the circuit collide more frequently with the lattice ions.

[@HitanshuTheBoy]

Your explanation is too fast. Can you please try to slow down in your next videos. Thank you

[@saras8166]

You can slow down videos in the options if you need to.

[@kingrobert7246]

I watch it on x2 there's really no need for him to slow down

[@nikanoos]

did you invent physiscs

[@mariehill6547]

How would you calculate the resistance from the graph? Because I/V= 1/R not R

[@youngwolf6896]

Taylor Shill multiply by the power (-1)

[@unravel9716]

Why can't I comprehend what I hear 😐

[@unravel9716]

Back here again I get everything now 🫡

[@jaredbrandy4432]

weird flex