Basic Elements of Electrical Circuits

• Resistor• Inductor• Capacitor• Voltage source• Current source

Resistor Ohm

Capacitor Farad

Inductor Henry

Symbols of basic elements:

Resistor and Resistance

• The circuit element used to model the current –resisting behavior of a material is the resistor.

• The resistance R of an element denotes its ability to resist the flow of electric current

• it is measured in ohms (Ω)

• Voltage across a resistance is given by V=IR

Inductor and inductance

• Any coil of wire is an inductor.

• Inductance is the property of inductor

•Inductor stores energy in the form of magnetic field.

•The current through and voltageacross an inductor is given by

dt

dILV

VdtL

I

1

Capacitor and capacitance

•Any two conductors separated by a dielectric form a capacitor.

• Capacitance is the property of capacitor

•It stores energy in the form of electric field.

•The current through and voltage across a capacitor is given by

dt

dVCI

IdtC

V

1

Concept of open circuit and short circuit

• What if R = ?

• i(t) = v(t)/R = 0

In open circuit Current = 0 ; Voltage at open circuit = v(t)

The Rest of

the Circuit

i(t)=0

+

–

i(t)=0

Open Circuit:

• What if R = 0 ?

• v(t) = R i(t) = 0 At short circuit Current = Maximum or infinite; voltage = 0

Short Circuit:

The Rest of

the Circuit

v(t)=0

i(t)

+

–

Concept of series and parallel Circuits

Series Connection:

Two elements are in series if one element is connected directly to the other with nothing coming in between.

Note: In series connection, same current will flow through all elements connected in series

Parallel Connection: Two elements are connected in parallelif both the ends are connected together.

House circuits contain parallel

circuits

The parallel circuit will continue

to operate even though one

component may be open

Only the open or defective

component will no longer continue

to operate

Note:

Examples of Parallel Circuits:

Series - Parallel Circuits

Circuits may contain a combination of series and

parallel components

Being able to recognize the various connections in

a network is an important step in analyzing these

circuits

Series - Parallel Circuits Contd….

THANK YOU