ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: filoballerx on May 01, 2011, 09:36:59 pm

Title: PHOTONICS!
Post by: filoballerx on May 01, 2011, 09:36:59 pm

can anyone give me some information for LDRs (light dependant resistors) PLEASE!!

Title: Re: PHOTONICS!
Post by: taiga on May 01, 2011, 10:05:16 pm

They are resistors that depend on light.

The resistance of the resistor, literally depends on how much light is flashed on it. You will generally get a graph indicating the response.

Attached is some stuff to do with the LDR and it's friends.

Source) Cheatsheet which can probably be found on VN

Title: Re: PHOTONICS!
Post by: Shark 774 on May 03, 2011, 07:01:53 pm

A reversed-biased photodiode is a similar thing to a LDR, right? The current allowed to flow will increase in both cases as the light intensity increases?

Title: Re: PHOTONICS!
Post by: Vincezor on May 03, 2011, 10:03:37 pm

Quote from: Shark 774 on May 03, 2011, 07:01:53 pm

A reversed-biased photodiode is a similar thing to a LDR, right? The current allowed to flow will increase in both cases as the light intensity increases?

However the current flowing through the photodiode is proportional to the light intensity... Can the same be said about the LDR? :S

Title: Re: PHOTONICS!
Post by: Shark 774 on May 04, 2011, 11:16:55 pm

Quote from: Vincezor on May 03, 2011, 10:03:37 pm

However the current flowing through the photodiode is proportional to the light intensity... Can the same be said about the LDR? :S

Hmmm... I think so, because the resistance of a photoresistor is proportional to the light intensity, hence the current flowing would be proportional to the light intensity.