Example 21.9Charging a Capacitor in an RC cireuit Charging a Capacitor in an RC

Question

Example 21.9Charging a Capacitor in an RC cireuit Charging a Capacitor in an RC Circuit An uncharged capacitor and a resistor are connected in series to a battery as shown in the figure, where = 12.0 v, c = 4.50 F, and R = 7.3 x 105 . The switch is thrown to position a. Find the time constant of the circuit, the maximum charge on the capacitor, the maximum current in the circuit, and the charge and current as functions of time. SOLVE IT Conceptualize Study the figure and imagine throwing the switch to position a as shown in figure (b). Upon doing so, the capacitor begins to charge. Categorize We evaluate our results using equations developed in this section, so we categorize this example as a substitution problem

Explanation / Answer

(A) 1/Req = 1/R + 1/R1 = 1/(7.3 x 10^5) + 1/(3.1 x 10^5)

Req = 2.18 x 10^5 Ohm

Ceq = C1 + C2 =4.50 + 4.60 = 9.10 uF = 9.10 x 10^-6 F

time constant = R C = 1.98 sec

(B) I = e / Req = 55 x 10^-6 A  

= 55 uA  

(C) Req = R1 + R2 = 10.4 x 10^5 ohm

1/Ceq = 1/C1 + 1/C2

Ceq = 2.27 x 10^-6 F

T = Req Ceq = 2.37 sec  

(D) Imax = (12)/(10.4 x 10^5) = 11.5 x 10^-6 A

= 11.5 uA  

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.