Open and short circuit in series and parallel network

Shorts and opens in series circuits

Short circuits

    A short circuit is a path of zero or very low resistance compared to the normal circuit resistance. In a series circuit, short circuits may be partial or full (dead short)

Effects due to short circuit

    Excess current due to short circuit can damage the circuit components, power sources, or burn the insulation of connecting wires. Fire is also caused due to intense heat generated in the conductors.

Protection against dangers of short circuit

    Dangers of short circuit can be prevented by means of fuses and circuit breakers in series with the circuit.

Open circuit in series circuit

    An open circuit results whenever a circuit is broken or is incomplete, and there is no continuity in the circuit.

Causes for open circuit in series circuit

    Open circuits, normally, happen due to improper contacts of switches, burnt out fuses, breakage in connection wires and burnt out resistors etc

Effect of open in series circuit

• No current flows in the circuit.
• No device in the circuit will function.
• Total supply voltage/ source voltage appear across the open.

Shorts and opens in parallel circuits

Shorts in parallel circuit

A short circuit exists when current can flow from the positive terminal of the power source through connecting wires and back to the negative terminal of the power source without going through any load.

This causes reduction of circuit resistance almost to zero.

The result is that a very high current in the order of hundred times of the normal current will flow through the short circuit.

    For a fuse to protect a parallel circuit, it should be placed in the circuit where the total current flows or else each branch must have a fuse.

Opens in parallel circuit

    An open in the common line at point A as shown in Fig 5 causes no current flow in that circuit whereas an open in the branch at point B causes no current flow only in that branch.