Basic Electricity is Applied to Welding
Electricity :
Electricity is a kind of invisible energy which is capable of doing work such as :
— burning of lamps.
— running of fans , motors , machings etc.
— producing heat.
Electric Current :
Electrons in motion is called current . The rate of flow of electrons is measured in Amperes . Hence the unit of electric current is Ampere . The measuring instrument of electric current is ampere meter or ammeter.
Electric Pressure :
It is the pressure which makes the electric current to flow . It is called voltage or electromotive force ( emf ) . Its measuring unit is volt . The measuring instrument is called volt - meter .
Electric Resistance :
It is the property of a substance to appose the flow of electric current passing through a current regulator . Its measuring unit is ohm and the measuring instrument is ohmmeter or megger .
Resistance of a substance ( conductor ) depends on the :-
— Nature of the conductor .
— Length of the conductore .
— Cross - section of the conductors . — Temperature of the conductors .
Conductor :
The substance through which electricity passes is called conductor . Copper , Aluminium , steet , carbon etc. are examples of conductor .
Insulator :
The substance through which electricity does not pass is called insulator . Glass , Mica , Rubber , plastie , dry wood , day cotton etc. are examples of insuiare .
Alternating Current (AC) :
Electric current which changes its direction and magnitute at a certain numbe of times per second is called Alternating current .
Its rate of change is called frequency i.c. Hertz ( Hz ) . In India the frequency of A.C. is 50 cycles per second . 50 cycles per second means it changes its divection 50 times per second.
Direct Current (DC) :
Electric current which alwaye flows in a perticular direction is known as Direct current . Here ponticular direction means negative to positive ( electronic direction ) and positive to negative ( conventional direction ) .
Ohm's Law :
It is one of the most widely applied laws of electrical science.
It is the relationship of current , roltage and resistance , which was studied in 1827 by George . S. ohom , a mathematician .
The law states :-
In an electrical circuit , at constant temperature , the curnent varies dinectly as the voltage and invensly as the resistance . i.c. current increses when voltage increase and current decreases when resistance increases .
