Week6_1 - RC Circuits A direct current circuit may contain...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
1 RC Circuits ± A direct current circuit may contain capacitors and resistors, the current will vary with time ± When the circuit is completed, the capacitor starts to charge ± The capacitor continues to charge until it reaches its maximum charge (Q = C ε ) ± Once the capacitor is fully charged, the current in the circuit is zero
Background image of page 1

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

View Full DocumentRight Arrow Icon
2 Quiz 2 on Wednesday ± Chapter 20
Background image of page 2
3 Quiz 2 Wednesday ± Chapter 20
Background image of page 3

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

View Full DocumentRight Arrow Icon
4 Charging an RC Circuit ± As the plates are being charged, the potential difference across the capacitor increases ± At the instant the switch is closed, the charge on the capacitor is zero ± Once the maximum charge is reached, the current in the circuit is zero ± The potential difference across the capacitor matches that supplied by the battery
Background image of page 4
5 Charging Capacitor in an RC Circuit ± The charge on the capacitor varies with time ± q = C ε (1 – e -t/RC ) = Q(1 – e -t/RC ) ± τ is the time constant ± τ =RC ± The current can be found () tRC It e R ε =
Background image of page 5

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

View Full DocumentRight Arrow Icon
6 Time Constant, Charging ± The time constant represents the time required for the charge to increase from zero to 63.2% of its maximum ± τ has units of time ± The energy stored in the charged capacitor is ½ Q ε = ½ C ε 2
Background image of page 6
7 Discharging Capacitor in an RC Circuit ± When a charged capacitor is placed in the circuit, it can be discharged ± q = Qe -t/RC ± The charge decreases exponentially
Background image of page 7

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

View Full DocumentRight Arrow Icon
8 Discharging Capacitor ± At t = τ = RC, the charge decreases to 0.368 Q max ± In other words, in one time constant, the capacitor loses 63.2% of its initial charge ±
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/02/2008 for the course PHYS 102 taught by Professor N/a during the Spring '08 term at Drexel.

Page1 / 23

Week6_1 - RC Circuits A direct current circuit may contain...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online