An a.c. generator/dynamo
It produces alternating current energy from mechanical energy of rotation of a coil. It is based on the phenomenon of EMI. The form of e,m,f. induced is e=e0sin ωt.
A d.c. generator/dynamo
It produces direct current energy from mechanical energy of rotation of a coil. It principle and working are same as those of a.c. generator. There is only a little change in the design of the generator. Slip Ring arrangement used in a.c. generator is replaced by Slit Ring arrangement or commutator arrangement in d.c. generator.
A d.c. motor
D.C. motor converts direct current energy from a battery into mechanical energy of rotation. It is based on the fact that when a coil carrying current is held in a magnetic field, it experiences a torque, which rotates the coil. The efficiency of d.c. motor is given byby η = E/V= back e.m.f./e.m.f. of battery The efficiency becomes maximum, when E = V/2 A motor starter is a variable resistance, which protects the motor from damage, when it is switched on. It is connected in series with the motor coil.
A choke coil
It is a pure inductor used for controlling current in a.c. circuit. Through pure L , Phase difference between E and I is ѳ = 90.
It is an electrical device, which is used for changing alternate voltages. It is based on the phenomenon of mutual induction. If np is number of turns in primary coil and ns is the number of turns in secondary coil, then Es /Ep = Is /Ip = ns /np = K Where K is a constant called Transformation Ratio.
It is powerful equipment used for generating high voltages of the order of 105 volt from a battery of a few cells. It is based on the phenomenon of mutual induction.
Some instruments and use
1. Accumulater–Instrument that conserve electricity which uses if necessary.
2. Aerometer–Instrument that uses to the measure of density and weight of air.
3. Altimeter— To measure the height of the flying airplane.
4. Ammetter–To measure the electricity
5. Anemometer–To measure power and velocity of air.
6. Audiometer–To measure frequency of air.
7. Audiometer–To use as earphone.It uses in the ear.
8. Ballistic GalvanometerIt–Ballistic GalvanometerIt uses to measure minimum electricity.
9.Barometer –To measure air prassure.
10.Barograph –To measure difference in pressure in inverment.
11.Binocular –To see the farest thing.
12.Calipers –To measure the cylindrical inner and outer part. It also uses width.
13.Calorimeter –It made of cupper. It uses to measure of heat.
14.Carburetter –To mixture of air and petrol in the inner part of petrol engine.
15.Cardiograph –It count heart beat.It also called electrocardio graph.
17.Chronometer –It uses on th boat to currect time.
18.Campass Box –It usese to right path.
19.Computer –It is a mathemetical composition system which solves the probelem.
20.Cyclotron –By this instrunment active partical like electron, proton will accelerated.
21.Densitymeter –It uses to density measurement.
22.Dictaphone –It uses to record the audio.
23. Namanmapi–It uses the naman of anywhere.
24.Dynamometer –It uses to measure the power of mechines.
25.Epidiascope –It uses projection at any covers.
26.Fathometer –It measures the depth of the sea.
27.Galvanometer –It instrument used micro electric corcuit’s unit and direction.
28.Geiger-Muller Counter –It uses the radio active source activity.
29.Gravimeter –By this instrument we measure the oil on on yhe surface of water.
30.Gyroscope –By this instrunment we measure the movement of circular motion moving body.
31.Hydrometer–By this instrunment we measure the v/s density.
32.Hydrophone –It uses the counting of the wave of noice in ses.
33.Hygrometer –By using it we measure the temprature of the inverment.