Electrical system

Sources

Main electricity

Electric cells

Main socket

Have INPUT(something we use) and OUTPUT(result)

Must be close(complete) circuit for it to work

If open, then its an incomplete(open) circuit

Materials

Insulators

Conductors

metals

non-metals such as plastic, wood etc

Flow of elctrons in one direction in a circuit is called an electric circuit

Move from negative terminal to positive terminal

Current

Conventional

Electron

Positive to negative

Negative to positive

Measure electric current

Ammeter (SI unit: amprere (A))

1000mA = 1A

Connect in series

Positive terminal is connected to positive side of the cell and vice versa

Air con needs 10A to work while a light bulb in lamp needs 0.5A

Potential Difference (p.d.)

p.d. btw 2 points is a measure of the amt of potential energy that is changed into other forms of energy when an electron passes between these 2 points

Measure via Voltmeter (SI unit: volt (V))

Connected in parallel across the bulbs

Positive terminal connected to positive side of the cell and vice versa

Positive terminal is red while Negative terminal is black

Resistance

Like an obstacle against the flow of electrons

Higher resistance, lower power

Resistors

Variable resistors (rheostat)

Fixed resistors

Arrangement of circuits

Series

Parallel

  1. Prallel circuit divides into 2 or more branches and has electrical components in each branch
  2. The current from the battery divides and flows through each branch
  3. If one bulb is removed or broken, the other bulbs remain lit becuz the circuit remains closed.
  1. Each component is joined one after the other to form a single path
  2. The current that flows through each of the component is the same
  3. If one bulb is removed or broken, no current flows. The other bulbs do not light up becuz the circuit is now open

Resistors

In parallel, total resistance decrease

In series, total resistance increase

Effects

Heating (electrical energy -> heat energy). Higher resistance, more heat generated.

Magnetic effect

Can magnetise a magnetic material

Chemical

Electroplating

Extration of metals

Allows metallic objects to be covered with a thin layer of another metal

Solid compound heated until it melts. Electric current passed through the molten compound which breaks down to give the metal.

Electrolysis (Electricity break down)