2 r v 0 to the external load and to the internal

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Unformatted text preview: ry is delivered − I 2 R + ∆V = 0 to the external load and to the internal resistance 303L: DC Circuits (Ch.28) 303L: DC Circuits (Ch.28) 1 RC circuits RC circuit RC circuits charging a capacitor discharging a capacitor contains a series combination of a resistor and a capacitor • Kirchhoff’s loop rule: • Initial current I0 = dq dt ( q (t ) = Cε 1 − e − t RC I (t ) = ε R − t RC − • Kirchhoff’s loop rule: I= R Q = Cε dq ε q =− dt R RC ⇒ ) = Q (1 − e e −t contains a series combination of a resistor and a capacitor ε • Maximum charge on C I= RC circuit q ε − − IR = 0 C q (t ) = Q e − t ) I (t ) = − Q −t e RC dq dt ⇒ q − IR = 0 C dq q =− dt RC RC RC RC - time constant 303L: DC Circuits (Ch.28) 303L: DC Circuits (Ch.28) Electrical Meters Electrical Meters Galvanometer Ammeter Main component in analog meters for measuring current and voltage A device that measures current • The • Coil of wire free to rotate on a charges through pivot in a magnetic field provided by the must pass ammeter directly series connection a permanent magnet • Coil carries a current I • Ideally, an ammeter should have zero torque resistance so that the current being causes the coil to twist ~I • Calibrated instrument can measured is not altered be used to measure I or ∆V • Small shunt resistor in parallel reduces I through a galvanometer and am...
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This document was uploaded on 01/15/2014.

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