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ELECTRICITY. Value of mains supply = 230V. ELECTRICITY. Fuse is used as a safety device Prevents too much current flowing in circuit. ELECTRICITY. Power of appliances measured in watts (W). ELECTRICITY. Plug wires – colours Live – brown Neutral – blue Earth – green/yellow
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ELECTRICITY • Value of mains supply = 230V
ELECTRICITY Fuse is used as a safety device Prevents too much current flowing in circuit.
ELECTRICITY Power of appliances measured in watts (W)
ELECTRICITY Plug wires – colours Live – brown Neutral – blue Earth – green/yellow Fuse in live position
ELECTRICITY Double insulation – no earth wire required as casing of appliance is plastic –non conductor
ELECTRICITY Human being is a conductor of electricity so do not touch wires ,do not come into contact with water with electricity.
Electricity • PARTS OF THE RADIO • 1. AERIAL - PICKS UP ALL SIGNALS • 2. TUNER – SELECTS ONE PARTICULAR SIGNAL
TELECOM • 3. DECODER – SEPARATES CARRIER WAVE FROM AUDIO WAVE • 4. AMPLIFIER – MAKES BIGGER COPY OF AUDIO WAVE
TELECOM • 5. BATTERY – SUPPLIES ENERGY TO AMPLIFIER • 6. LOUDSPEAKER – CHANGES ELECTRICAL ENERGY TO SOUND ENERGY
TELECOM • COLOUR MIXING • 3 PRIMARY COLOURS – RED , GREEN , BLUE TOGETHER MAKE WHITE
TELECOM • RED AND GREEN GIVE YELLOW. • RED AND BLUE GIVE MAGENTA • GREEN AND BLUE GIVE CYAN
TELECOM • GEOSTATIONARY SATELLITES ARE AT A HEIGHT OF 36 , 000Km ABOVE THE EARTH • THEY HAVE A 24 HR ORBIT
TELECOM • SIGNALS ARE MICROWAVE AND TRAVEL IN A STRAIGHT LINE TO AND FROM THE SATELLITE.THEY CANNOT CURVE IN THE EARTH`S ATMOSPHERE
TELECOM • OPTICAL FIBRES USED TO CARRY INFORMATION BY TOTAL INTERNAL REFLECTION. LIGHT TRAVELS AT A SPEED OF 200 , 000 , 000 M/S
ELECTRICITY • EQUATIONS • Q = I x T V = I x R • P = I x V P = E / t • P = V2 / R P = I2R • RT = R1 + R2 • 1 /RT = 1/R1 + 1/R2
ELECTRICITY • RULES FOR SERIES AND PARALLEL CIRCUITS • VOLTAGE SPLITS UP IN A SERIES CIRCUIT • CURRENT STAYS THE SAME IN A SERIES CIRCUIT • VOLTAGE STAYS THE SAME IN A PARALLEL CIRCUIT • CURRENT SPLITS UP IN A PARALLEL CIRCUIT
ELECTRICITY • VOLTMETERS MEASURE VOLTAGE AND GO ACROSS THE COMPONENT • AMMETERS MEASURE CURRENT AND ARE WIRED IN SERIES WITH THE COMPONENTS. • CIRCUIT COMPONENTS INCLUDE RESISTORS , BULBS ETC.
ELECTRICITY • MAINS ELECTRICITY • WIRES IN THREE PIN PLUG • 1. BROWN LIVE 2. BLUE NEUTRAL • 3. GREEN / YELLOW EARTH • FUSE IS A SAFETY DEVICE WIRED IN THE • LIVE PIN • EARTH WIRE NOT NEEDED FOR DOUBLE INSULATED APPLIANCES , THEY HAVE A PLASTIC CASING
ELECTRICITY • MAINS ELECTRICITY • THREE TYPES OF CIRCUIT • 1. THE LIGHTING CIRCUIT 15A FUSE 2. THE RING MAINS CIRCUIT 30A FUSE 3. THE COOKER CIRCUIT 45A FUSE • ALL ARE WIRED IN PARALLEL IF ONE GOES OUT THE OTHERS STAY ON LESS WIRE USED SO MONEY IS SAVED
ELECTRICITY • ELECTRIC MOTORS • COIL OF WIRE CARRYING CURRENT SURROUNDED BY A PAIR OF MAGNETS • THE MORE TURNS ON THE COIL AND THE STRONGER THE MAGNET , THE FASTER THE COIL GOES.
ELECTRICITY • TWO COILS OF WIRE WITH AN IRON CORE , THE PRIMARY COIL AND THE SECONDARY COIL • TRANSFORMERS • NP /NS = VP / VS • IP x VP = IS x VS
HEALTH • TYPES OF THERMOMETER • 1. THE LAB THERMOMETER 2. THE CLINICAL THERMOMETER BOTH LIQUID IN GLASS THERMOMETERS 3. THE DIGITAL THERMOMETER • DIFFERENCE BETWEEN LAB AND CLINICAL THERMOMETERS, SIZE,SCALE, MAGNIFIER IN CLINICAL THERMOMETER,KINK