Static electricity refers to the buildup of electric charge on the surface of objects and can be contrasted with current electricity which is delivered through wires. There are 5 types of electric discharge that can occur. Static electricity can be dangerous in places like operating theaters, around computers, and when refueling if flammable vapors are present as sparks from static discharges can ignite them. Current is the flow of electric charge through a medium like a wire and is measured in amperes. Potential difference refers to the difference in electric potential between two points in an electric field and is measured in volts. Capacitors are electrical components that store energy in an electric field and are measured in farads.

1. BY : ERICA P

2. Static electricity
 Refers to the build-up of electric charge on the
surface of the objects.
 It can be contrasted with current,electricity which
can be delivered through wires as a power
source.
 There are 5 types of electric discharge (
Spark,Brush discharge,propagating brush
discharge,cone discharge and corona
discharged)

3.  Lighting
 Refuelling
Sparks from statics electricity can be dangerous when flammable vapour is present.
 Operating Theaters
Dust and germs attracted by charged objects.We need to ‘earthed’ all the
equipment.
 Computers
Computers require simillar ‘anti-static’ conditions as they are vulnerable to
electrostatic damage.

4. Uses of Static Electricity
 Flue-ash precipitation
 Photocopiers
 Inkjet printers
 Painting cars

5. Electric Current
→ is a flow of electric charge through a medium.
→ Charge typically carried by moving electrons such as
wire.
→ The SI unit is AMPERE.
→ Is measured using AMMETER.

6. − Heating and lighting
− Magnetic
− Chemical

7.  Series
current is the same at all the points in a series
circuits.
 Parallel
The sum of the current in the branches of a
parallel circuit equals the current entering
or leaving the parallel section.
Series and Parallel circuits

8. Potential Difference
* The difference in electric potential between two
pointsin an electric field.
* measured in volts
* The work that has to be done in transferring unit
positive change from one point to the other.

9. Resistance
 The opposition of a conductor to current called
RESISTANCE.
 The formulae R=V/I
 the smaller the I is for a given V,the greater R.
 The ohm is the resistance of a conductor.

10. Ohm’s Law
 Metallic Conductor (current through a metallic
conductors is directly propotional to the
voltage)(there are called ohmic or linear conductors)
 Semiconductors diode
 Filament Lamp
 Variation of resistance with temperature
 Variation of resistance with light intensity

11.  In series same current flows through
each and total voltage.
 In parallel the voltage between the
ends of each is the same.

12.  Is a passive two terminals electrical
component used to store energy in electric
field.
 its measured by farads(F)
 Smaller units such as the microfarad are
more convenient.
 A capasitors store electric charge and its
useful in many electric circuits

13.  Practical capacitor
 Polyester capacitor
 Electrolytic capacitor

14.  Charging
It can be charged by connecting a battery across
it.During the charging,there is brief flow of lectrons
round the circuits.A momentary current would be
detected by a sensitive ammeter.
 Discharging
When a conductor is connected across a charged
capasitors,there is a brief flow of electron from the
negatively charged plate to the positively one.

15. Electric Power
 Is the rate at which electric energy is transferred by
an electric circuits
 The SI of power is watt

16.  Filament lamps
Is a small coiled coil of tungsten wire,which
become white hot when current flows throught
it.Its contain nitrogen and argon,not air.
 Fluorescent strips
Transfer only 10% of the electrical energy supplied
to light; 90% becomes heat.
 Compact Fluorescent lamps
Last up to 8 times longer.used about 5 less energy
than others.
Electric lighting

17.  Heating elements
 Three-heat switch
 Fuses
Electric heating

18.  Circuits in parallel
 Switches and fuses
 Staircase circuits
 Ring main circuits
 Fused plug
 Earthing and safety
 Circuits breakers
 Double insulation

19. Danger of electricity
 Electric shock
electric shocks occurs if current flows from an
electric circuit through a person body’s to earth.Its
causes by damaged insulation or faulty wiring.
 Fire risks

20. How to AVOID!!
1. Switch off the electrical supply to an appliance
before starting repairs.
2. Use plugs that have earth pin.
3. Do NOT allow appliances or cables to come into
contact with water.
4. Do NOT have long cables trailing across
room,under carpet or in other conditions.
5. Use plugs that have the correct fuse
6. Do NOT attach to many appliances to a circuit
7. Dont overload circuits by using to many adapters