An electric circuit is a closed loop that allows electric current to flow from a power source through various components like switches, fuses, and loads, and back to the source. The main parts of a circuit include an electrical source that delivers power, controlling devices that regulate the current, protection devices that prevent damage, conducting wires or paths, and loads that use the power. Circuits can be open or closed, and classified as series, parallel, or a combination depending on how the components are connected.

1. Electric Circuit and Circuit Elements

2. Electric Circuit
The system in which electric current
can flow from source to load through
one path and after delivering energy at
load, the current can return to the
other terminal of source through
another path is referred as electric
circuit.

3. Main Parts of an Electric Circuit
 Electrical Sources (for delivering electricity to the
circuit and these are mainly electric generators and
batteries)
 Controlling Devices (for controlling electricity and
these are mainly switches, circuit breakers, MCBs etc.)
 Protection Devices (for protecting the circuit from
abnormal conditions and these are mainly electric
fuses, MCBs, Switchgear systems)
 Conducting Path (to carry current one point to other in
the circuit and these are mainly wires or conductors)
 Load

4. Basic Properties of an Electric
Circuit
 A circuit is always a closed path.
 A circuit always contain an energy source which acts as
source of electrons.
 The electric elements include uncontrolled and
controlled source of energy, resistors, capacitors,
inductors, etc.
 In an electric circuit flow of electrons takes place from
negative terminal to positive terminal.
 Direction of flow of conventional current is from
positive to negative terminal.
 Flow of current leads to potential drop across the
various elements.

6. Types of Electric Circuit
 Open Circuit-If due to disconnection of any part of an
electric circuit if there is no flow of current the circuit
is said to be open circuited.

7.  Closed Circuit-If there is no discontinuity in the
circuit and current can flow from one part to another
part of the circuit then the circuit is said to be closed
circuit.

8. Electric circuits can further be
categorized according to their
structural features.
Series Circuit
Parallel Circuit
Series Parallel Circuit.

10. Voltage and Current are the two
basic features of an Electric
Element which supply energy
to the circuit.
Active Components

11. Passive Components
 The element which receives energy (or
absorbs energy) and the either converts it
into heat or stored it in an electric or
magnetic field called Passive Element.
Example: Resistor, Inductor, Capacitor etc.

12. Passive Components
Component Symbol Basic Measure (Unit)