V = IR
idt + v(0) C
, i = 0 for DC
V − I relationships for a resistor, inductor and capacitor.
Kirchhoff’s Voltage Law (KVL)
Kirchhoff‟s Voltage Law states that the algebraic sum of voltages around each loop at any instant of time is
Σ voltage drops = Σ voltage rises
Kirchhoff’s Current Law (KCL)
Kirchhoff‟s Current Law states that The algebraic sum of currents a node at any instant is zero.
Σ currents in = Σ currents out
Current: the directed flow of electrons (charge) called current. It is denoted by I. units are Amps
Electrical potential: charged body capacity to do work is known as its electrical potential.
Potential difference: difference in potentials of two charged bodies is called Potential difference
Power: the rate at which an electrical work done in electrical work is called power. It is denoted by P. units are
Electrical work: Electrical work is said to be done when there is transfer of charge. It is denoted by W. units
Energy: capacity to do work is called energy.
Electrical Network: A combination of various electric elements (Resistor, Inductor, Capacitor, Voltage source,
Current source) connected in any manner what so ever is called an electrical network
Classification of element:
We may classify circuit elements in two categories, passive and active elements.
Passive Element: The element which receives energy (or absorbs energy) and then either converts it into heat
(R) or stored it in an electric (C) or magnetic (L) field is called passive element.