Is the Formula for Voltage Drop Across Capacitor Opposite of Resistor?

Click For Summary
SUMMARY

The discussion centers on calculating the voltage drop across capacitors in series, specifically a 60μF and a 30μF capacitor powered by 60V. The formula for voltage drop across resistors, R1 = R1/(R1+R2), is contrasted with the voltage drop across capacitors, which is derived from the equation Q = C·V. It is established that equal amounts of charge are added to each capacitor in series, and the voltage drop can be confirmed by multiplying the derived equations with the total voltage. The importance of deriving these equations for clarity and accuracy is emphasized.

PREREQUISITES
  • Understanding of capacitor behavior in series circuits
  • Familiarity with the equation Q = C·V
  • Basic knowledge of voltage division in electrical circuits
  • Ability to derive formulas for voltage drop across capacitors and resistors
NEXT STEPS
  • Study the derivation of voltage drop formulas for capacitors in series
  • Learn about the implications of charge conservation in series circuits
  • Explore practical applications of capacitors in electronic circuits
  • Investigate the differences between resistive and capacitive voltage division
USEFUL FOR

Electrical engineering students, electronics hobbyists, and anyone involved in circuit design or analysis, particularly those focusing on capacitive components.

Joel Kee
Messages
13
Reaction score
0

Homework Statement


I'm trying to calculate the voltage drop across a 60uF and a 30uF capacitor in series, powered by 60V. Is the formula for voltage drop across capacitor opposite of the formula for resistor, where resistor is R1=R1/(R1+R2) while capacitor is C1=C2/(C1+C2)?

Homework Equations

The Attempt at a Solution

 
Physics news on Phys.org
Joel Kee said:
Is the formula for voltage drop across capacitor opposite of the formula for resistor, where resistor is R1=R1/(R1+R2) while capacitor is C1=C2/(C1+C2)?
The symbols on the left side don't make sense. The right side is useful, but you should probably derive those equations to be sure.
 
mfb said:
The symbols on the left side don't make sense. The right side is useful, but you should probably derive those equations to be sure.
My bad, the eqs are supposed to be multiplied with the total voltage.
 
It is far better that you be confident at deriving such formula yourself using basic knowledge.

The crux of the matter is that when connected to a source, equal amounts of charge are added to each of the series-connected capacitors.
Use this fact, together with Q = C·V, to confirm or disprove the formula you wrote.
 
Joel Kee said:
My bad, the eqs are supposed to be multiplied with the total voltage.
Still your bad. R1=R1/(R1+R2) ? Etc.
 
rude man said:
Still your bad. R1=R1/(R1+R2) ? Etc.
V1=[R1/(R1+R2)]V

My bad.
 

Similar threads

Simple voltage divider -- why does this work?
  • · Replies 8 ·
Replies
8
Views
3K
Calculating the voltage across capacitors and resistors with switches
  • · Replies 2 ·
Replies
2
Views
921
Engineering Calculating the voltage at a certain Resistor
  • · Replies 3 ·
Replies
3
Views
2K
Engineering Calculating voltage across resistors/capacitors in a circuit
  • · Replies 4 ·
Replies
4
Views
2K
Engineering Charge Redistribution in a Capacitor Bank/DAC
  • · Replies 22 ·
Replies
22
Views
5K
Calculating R1 and R2 for Opto-Triac Output Circuit
  • · Replies 34 ·
2
Replies
34
Views
6K
Computing AC voltage in a complex filter
  • · Replies 15 ·
Replies
15
Views
2K
Two-layer dielectric, four-capacitor model vs three-capacitor model
  • · Replies 5 ·
Replies
5
Views
687
Engineering Voltage in capacitors within an Energy Harvester
  • · Replies 4 ·
Replies
4
Views
2K
Final voltage across the capacitor
  • · Replies 4 ·
Replies
4
Views
7K