Electrical Circuits

1. What is a circuit?

A closed pathway that allows transfer of electrical energy.

2. Basic Parts of Circuit

Basic parts of a circuit: Load (Receiver) (light bulb)

Power Source (battery)

Wires

Switch

LOAD (Receiver):

The part of the circuit that changes electrical energy into another form of energy. Example: electrical

energy is transformed by the load of the light bulb to light and thermal energy when the light is turned on.

3. Series Circuit

Series Circuit: a circuit in which all parts are connected in a

single loop. If one part breaks the circuit will not work.

If bulb A burned out, no current could flow through the circuit.

A B C

If bulb B burned out, no current could flow through the circuit

A B C

Question: What would happen if bulb C burned out?

A B C

Refrigerator Example:If your refrigerator was wired by a series circuit and one light bulb burned out, the whole refrigerator would stop working.

4. Parallel Circuits

Parallel Circuita circuit in which all parts are side by side

on different branches.

If bulb A burned out there would still be current the could flow through the

circuit.

A

B

C

If bulb B burned out there would still be current the could flow through the

circuit.

A

B

C

Question: What would happen if bulb C burned out?

A

B

C

Quick Review:

Sample Question 1: Which circuit is a parallel circuit?

A B

Sample Question 2:This is a parallel and series circuit mixed together.

What would happen if Bulb C burned out? Would the circuit still work?

C

AB

D

Sample Question 3:This is a parallel and series circuit mixed together.

What would happen if Bulb B burned out? Would the circuit still work?

A

CB