Calculate the Resistance of the RC circuit so that LED just stays on

Click For Summary

Discussion Overview

The discussion revolves around calculating the resistance in an RC circuit to ensure that an LED remains lit. The circuit includes a 12V battery, a capacitor, a resistor, and an LED with specific voltage and current ratings. The context is primarily homework-related, involving theoretical calculations and circuit analysis.

Discussion Character

  • Homework-related, Technical explanation

Main Points Raised

  • One participant presents a circuit with a 12V supply, a 12μF capacitor, a resistor, and a 2V LED, seeking to calculate the required resistance for the LED to stay on.
  • The participant calculates the capacitive reactance (Xc) as approximately 1326.3 Ω using the formula Xc = 1/(2∏fC).
  • Another participant questions the feasibility of using a 10 Hz frequency with a battery, suggesting it may be unconventional.
  • Some participants express concern about the original poster's engagement with the problem, indicating a lack of interest in further discussion.

Areas of Agreement / Disagreement

There is no clear consensus on the approach to the problem, and multiple viewpoints regarding the circuit's configuration and the use of frequency remain. The discussion appears unresolved.

Contextual Notes

The calculations presented depend on assumptions about the circuit's behavior at the specified frequency, and the implications of using a 10 Hz frequency with a battery are not fully explored.

rhiannynd
Messages
1
Reaction score
0
In a simple series circuit there is a 12V supply battery, 12μ6 F capacitor, a Resistor, and a 2v drop LED with an imax of 30mA. frequency is 10Hz
Calculate the resistance of the resistor so that the LED just stays on.

Homework Equations


Resistance of Capacitor Xc = 1/2∏fC
P=VI
V=IR
Impedence = √R^2+Xc^2



The Attempt at a Solution



Xc = 1/2∏x10x12x10^6
=1326.3 Ω
P=vxI
P = 12 x 0.03A
=0.36w

i have no idea what else to do ! any help would be greatly appreciated please please please
 
Physics news on Phys.org
A battery with 10 Hz? That's a new one on me.
 
So, is Rhian (PS: welcome to PF) out of trouble now ?
 
BvU said:
So, is Rhian (PS: welcome to PF) out of trouble now ?

He/she doesn't seem interested in pursuing this fascinating ac battery problem, all the 'please pleases' notwithstanding ...
 

Similar threads

Equivalent resistance with a capacitor
  • · Replies 11 ·
Replies
11
Views
8K
Engineering Impedance angle in RL and RC circuits
  • · Replies 4 ·
Replies
4
Views
2K
Engineering Thevenin Theorem seems to not work in this 1 bit RAM RC circuit
  • · Replies 2 ·
Replies
2
Views
2K
Calculating Copper Wire Gauge for Resistance Thermometer Bridge Circuit
  • · Replies 6 ·
Replies
6
Views
2K
Engineering Solve 2 Loop RC Circuit: Find Q(topen)
  • · Replies 8 ·
Replies
8
Views
4K
Engineering When is a RC circuit predominantly capacitive or resistive?
  • · Replies 1 ·
Replies
1
Views
5K
Engineering Question about this simple LED circuit with potentiometer
  • · Replies 9 ·
Replies
9
Views
3K
Engineering Transient Response RC series circuit
  • · Replies 1 ·
Replies
1
Views
2K
Deciding batteries for my circuit
  • · Replies 3 ·
Replies
3
Views
2K
Engineering Analyzing an RC Circuit: Solving for Time Constants and Resistance
  • · Replies 10 ·
Replies
10
Views
4K