PHY2049ch25B%282-8-10%29

# PHY2049ch25B%282-8-10%29 - Last time we developed the idea...

This preview shows pages 1–7. Sign up to view the full content.

eq q eq C eq q + eq q Last time we developed the idea that combinations of capacitors can be reduced to an equivalent single capacitor with capacitance C eq and charge (separation) q eq . For capacitors in parallel: The rules we found were that: + 1 C 2 C 2 q 1 q V V V The voltage across each cap is the same , V 1 = V 2 =…= V . eq 1 2 q q q ... =++ & eq 1 2 C C C ... + V 1 C q, 2 C 1 V 2 V For capacitors in series: The charge across each cap is the same , . 12 V V V ... = ++ & eq 1 2 11 1 ... CC C = q + q e q q q ... q = ==

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
All caps C =10 μ F All V = 10 V Find q 2 and V 2 for each circuit. Examples 1 2 3
C 1 = C 2 =10 μ F V = 10 V Find q 2 and V 2 . C 1 C 2 0 V 10 V + + C eq = C 1 |C 2 0 V 10 V + “C 1 series C 2 2 12 eq 1 2 1 C C 100 F CC | C 5 F 11 2 0 F μ == = = = μ + Now find , eq eq q C V (5 F)(10V) 50 C = = μ Example 1 eq q

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
C 1 = 10 μ F 0 V 10 V + C 2 = 10 μ F eq C5 F eq q5 0 C 0 V 10 V + Caps in series each have the same q i as q eq . 1 0 C = μ 2 0 C = μ Then, Looking for q 2 and V 2 , so must now work backwards 2 2 2 0 C V5 V C1 0 F μ == = μ Found: Note also that 1 1 1 0 C V 0 F μ = μ So, 12 V V 5V 5V 10V + =+= As it should for series caps. values are the answers.
Time saving rules of thumb for 2 equal caps in series: C C 0 V V + eq C C 2 = V 2 V 2 The equivalent capacitance is half the capacitance of the equal capacitors. The total voltage drop splits evenly between the two caps.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
C 1 C 2 10 V + 0 V C 1 |C 2 C 3 10 V + 0 V C 3 0 V 10 V eq 1 2 3 C( C | C ) | | C = “parallel” C 1 = C 2 =10 μ F V = 10 V Find q 2 and V 2 .
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 05/17/2011 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.

### Page1 / 22

PHY2049ch25B%282-8-10%29 - Last time we developed the idea...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online