Mobile Phone Repairing” The multi meter is an instrument which can measure resistance, voltage and current. Some multi meter also measure frequency. There are two type of control and terminal of a multi meter.
Mobile Phone Repairing” Function/range switch” selects the function (voltmeter, Ammeter or ohm-meter) and the range for measurement. COM input terminal” Common ground used in all measurements. V input terminal” for voltage or ohm measurements. 200 ma input terminal” for small current measurements. 10 A input terminal” for large current measurements.
Mobile Phone Repairing Use Of Multi meter Voltmeter or Ohm-meter
Mobile Phone Repairing” Turn the meter on and select Ω for resistance measurement. Insert two wires in the jacks labeled VΩ and COM. The multi meter can now be used to in measure the resistance of a component connected between these two wires.
Mobile Phone Repairing” Remove all connected wires. Turn the meter on and select V for DC voltage or V mode for AC voltage. Insert a red wire in the jack labeled VΩ and a black wire in the jack labeled COM. When making voltage measurements, make certain the voltmeter is connected in parallel with the circuit components across which voltage is measured.
Remove all connected wires. Turn the meter ON and select A for ammeter mode, insert a red wire in the jack labeled “A” and a black wire in the ammeter is connected in series with the circuit components through which current is measured.
Atom are basic building blocks of matter, and cannot be chemically subdivided by ordinary means. Atom are composed of three types of particles. Protons, neutrons, and electron. Protons and neutrons are responsible for most of the atomic mass. Both the protons and neutrons reside in the nucleus.
- The mass of an electron is 9.108 X 10-28 grams.
- The mass of a proton is 1.672 X 10-24 grams.
- The mass of a neutron is 1.674 X 10-24 grams.
Proton has a positive (+) charge of 1.6 X 10-19 coulombs, neutrons have no charge… they are neutral. Electrons reside in orbitals around the nucleus. They have a negative charge (-) of equal amount as proton i-e 1.6 X 10.19 coulombs.
When a positive charged particle (+) like a proton is near a negative charged particle (-) like an electron, the electric field goes from one to the other. When particles have the same charge, they repel each other.