University:
Boston University
Course:
CAS PY 211 | General Physics I
Academic year:

2022
Views:

44

Pages:

7
Author:

pubicswprv

Experiment I Boston Voltage Divider University Slideshow Title Goes Here  Resistive Circuits 8 Capacitors Boston A University capacitor has capacity to store energy in the form of Slideshow Title Goes Here electrical charge producing a voltage across plates  Storage of energy is time dependent  This was NOT the case in purely resistive circuits.  Capacitance is measured in Farads [𝐹] 𝑖 = Instantaneous Current d𝑉 𝑖=𝐶 d𝑉 = Instantaneous rate of d𝑡 d𝑡 voltage change Capacitors are sometimes polarized 𝜀𝐴 𝐶= 𝑑 𝜀 = dielectic constant 𝐴 = Area of plate overlap 𝑑 = distance between plates NOTE: Directly connecting a capacitor to a voltage supply isn’t practical 9 Capacitors Boston The charge on a capacitor cannot change University Slideshow Title Goes Here instantaneously  The charge on the plates of the capacitor is given as Q = C*V  The current flowing into a capacitor after a long time interval (i.e., steady-state) is zero  Charge contained in the capacitor instead of flowing through the circuit 10 RC Circuits  RC circuits consist of a resistor and capacitor in series Boston University Slideshow Title Goes Here  A capacitor stores energy and a resistor placed in series with it control the rate at which it charges or discharges. 𝜏 ≡ 𝑅𝐶 𝑉𝑐 = 𝑉𝑠 1 − 𝑒 −𝑡Τ𝜏 VS = VR + VC VS = IR + Q/C 11 RC Circuits Boston Charge University Slideshow Title Goes Here  Discharge 12 Experiment II Boston Resistor – Capacitor (RC) Circuits University Slideshow Title Goes Here 13 Recap Boston What did you University Slideshow Title Goes Here today? 14