# DQ7C_solution - Discussion Question 7C P212, Week 7 RC...

This preview shows pages 1–2. Sign up to view the full content.

Discussion Question 7C P212, Week 7 RC Circuits The circuit shown initially has the capacitor uncharged, and the switch open. At time t = 0, the switch is thrown. Write all answers in terms of E , R, and C as needed. (a) At 0 + = t , immediately after the switch is thrown what is the current (0 ) + I ? + cap Consider applying KVL around the loop that includes the battery and the capacitor. - 0. At t=0 Q =0 0 0 (0 ) / + Δ− = Δ= = = cap cap VI R V I R I R E E ±E (b) After a very long time, what is the current I ? 12 When the capacitor is fully charged it acts like an open circuit. Hence all current flows through . The current is then I = / 2 . + RR R (c) After a very long time, what is the charge on the capacitor Q ? Consider the KVL that just consists of the capacitor and the one resistor. 0 -/ 0 0 22 ∞∞ −Δ = →= = = cap IR V IRQ C RQ C Q C R EE (d) Assume ( ) (1 exp( Qt Q t β =− ) ) gives the charge on the capacitor as a function of time. Use () 0 0 + + ⎡⎤ = ⎢⎥ ⎣⎦ dQ I dt and your answers to (a) and (c) to compute .

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## DQ7C_solution - Discussion Question 7C P212, Week 7 RC...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online