Circuits
Physics · परिपथ
📋Quick Overview
An electric circuit is a closed path through which current flows. It has a source (battery), conducting wires, a load (bulb/resistor), and a switch. Key topics for exams: Series vs Parallel comparison, Kirchhoff's laws, Wheatstone bridge, and Ammeter vs Voltmeter.
📖Kirchhoff's Laws
- •Kirchhoff's Current Law (KCL) / Junction Rule: Total current ENTERING a junction = Total current LEAVING. Simply: What goes in must come out. Based on conservation of charge.
- •Kirchhoff's Voltage Law (KVL) / Loop Rule: Sum of all voltages around any closed loop = 0. Simply: Energy gained = Energy lost in a closed loop. Based on conservation of energy.
📖Wheatstone Bridge & Potentiometer
- •Wheatstone Bridge: 4 resistors arranged in a diamond shape. When balanced: P/Q = R/S (no current through galvanometer). Used to find unknown resistance accurately.
- •Wheatstone Bridge was invented by Samuel Hunter Christie but named after and popularized by Sir Charles Wheatstone.
- •Potentiometer: Device to measure EMF (electromotive force) of a cell accurately without drawing current. More accurate than voltmeter.
- •Potentiometer works on the principle that potential drop across a wire is proportional to its length.