Electric circuit is used by electrons from a current source or voltage power.
A circuit or wiring diagram is a visual display of an electrical circuit.
The current flowing in an electrical or electronic circuit can suddenly increase when a component part fails. This can cause serious damage to other components in the circuit, or create a fire hazard. To protect against this, a fuse or a device called a "circuit breaker" can be wired into a circuit.
Usually low voltages or DC(Direct Current) is used by the electronic circuits, because load does not need very high power and just a few capacitors, resistors, I.C or other components will not require much power to perform their jobs and it will be powered by a 18650 lithium battery or any other battery source with required voltage and current.