Potential Divider: R(R+r)*E=V - Wrong Ans Explained

Click For Summary
SUMMARY

The discussion focuses on the potential divider equation R(R+r)*E=V, specifically in the context of light-dependent resistors (LDRs) and thermistors. It is established that in low light conditions, the resistance of the LDR increases, leading to a higher voltage across the LDR and a lower voltage across the thermistor. The correct answer to the problem is clarified to be option D, as the relationship between light intensity and resistance is critical in determining the output voltage in this circuit configuration.

PREREQUISITES
  • Understanding of potential divider circuits
  • Knowledge of light-dependent resistors (LDRs) and their behavior under varying light conditions
  • Familiarity with thermistors and their temperature-dependent resistance
  • Basic circuit analysis techniques
NEXT STEPS
  • Study the principles of potential dividers in electrical circuits
  • Learn about the characteristics and applications of LDRs
  • Explore the behavior of thermistors in temperature sensing applications
  • Investigate circuit simulation tools to model potential divider circuits
USEFUL FOR

Students studying electronics, educators teaching circuit theory, and hobbyists interested in sensor applications involving LDRs and thermistors.

Arun Raja
Messages
17
Reaction score
0

Homework Statement



http://puu.sh/dzujr/dcf208c4a5.png

Homework Equations


Potential divider concept--> R(R+r)*E=V

The Attempt at a Solution


When there is low light, resistance of LDR increase to produce light.

So, voltage across LDr increases and voltage across thermistor decrease-->lower temperature

so I think answer B , but it is wrong
 
Last edited by a moderator:
Physics news on Phys.org
This isn't really "advanced" physics (so the moderators might move it to another sub forum) but..

Arun Raja said:
When there is low light, resistance of LDR increase [strike]to produce light[/strike].

That first part is correct. More light (high illumination) causes the resistance of the LDR to fall. That will tend to "pull" the output voltage higher. That reduces your choices to B or D.

Now what about the thermistor?
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 45 ·
2
Replies
45
Views
4K
Replies
2
Views
3K
Replies
7
Views
4K
Replies
14
Views
2K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K