Kirchhoff’s Rules

Kirchhoff ’s rules:

1. Junction rule. The sum of the currents entering any junction in a circuit must equal the sum of the currents leaving that junction:

2. Loop rule. The sum of the potential differences across all elements around any closed circuit loop must be zero:

RC Circuits

Charging a Capacitor

Charging a Capacitor RC Circuits

RC Circuits

Charging a Capacitor

RC Circuits

Discharging a Capacitor

RC Circuits

Discharging a Capacitor

Electrical Meters

The Galvanometer

The principal components of a D’Arsonval galvanometer. When the coil situated in a magnetic field carries a current, the magnetic torque causes the coil to twist. The angle through which the coil rotates is proportional to the current in the coil because of the counteracting torque of the spring.

Electrical Meters

The Ammeter

Electrical Meters

The Voltmeter

Quick Quiz 7.1

A capacitor stores charge Q at a potential difference ∆V. If the voltage applied by a battery to the capacitor is doubled to 2∆V,

(a)the capacitance falls to half its initial value and the charge remains the same

(b)the capacitance and the charge both fall to half their initial values

(c)the capacitance and the charge both double

(d)the capacitance remains the same and the charge doubles.