science electrical systems

Front

Components of an electrical system

Back

Main components of an electrical system are the: 

• Cell 

• Electric charge 

• Wires 

• Electrical device (e.g. bulb)

Front

 electric current

Back

The rate at which electric charge flows is known as the electric current,

• We use an ammeter to measure the current in an electric circuit. The si unit of electric current is the ampere ( A)

• To measure the current in a circuit, an ammeter is connected in series within a circuit 

I = Q/T

I -> electric current

Q-> charge

T-> time (s)

Front

potential difference

Back

The amount of energy needed to move a unit charge from one point in an electric circuit to another point is known as the potential different,

-> A voltmeter measures the potential difference between two points in an electric circuit. The si unit of potential difference is the volt ( V) 

-> must be arranged in parallel

Q= W/V

Q -> charge

W -> work done

V -> voltage (potential difference)

Front

resistance

Back

The electrical resistance, R of an electrical component is a measure of how much the component opposes current.

Types of resisters :

• - fixed resistors - which has fixed, non adjustable electrical resistance

• - variable resistor -> which has a range of electrical resistance that can be adjusted

R = V/I

R -> resistance

v -> volts (potential difference)

I -> current

Front

Circuit breaker

Back

• The electrical DB box has many individual lever-like switches known as circuit breakers. The circuit breakers are connected to different parts of a household’s electrical system

• When the electric current is too large due to a faulty electrical appliance or wiring, a circuit breaker trips and cuts off the electrical supply. 

• This protests the appliance and the wiring from damage 

Front

formula of electrical energy

Back

Electrical energy( kWh) = power (kW) x Time (h)