Basic Electrical
Who was discovering electricity?
Most peoples give credit to Benjamin Franklin for discovers electricity in 1752.
What is electricity/Current?
Flow of free electrons is called current.
Define current:-
When electrons flow from any particular place like Copper or Aluminum wire will produce here current, our appliances operate by current.
What is Voltage?
Voltage is potential difference, pressure, or force, which is defined as the work per unit of charge to move a test charge between two points. In easy words that when we want passing current from any copper wire, so we need any force for flow of free electrons/current, so this force will provide voltage, the voltage tries to create a current flow and current flows when the circuit is complete. The voltage is sometimes described as the 'push' or 'force' of electricity, it is not really a force but Can help to imagine what happens. It is possible to have voltage without current, but current cannot run without voltage.
What is Charge?
Electric charge the basic property of matter, is caused by some elementary particles. Electric charge which can be positive or negative, occurs in discrete natural units and is neither created nor destroyed.
How many types of current?
There are two types of current;
1st Alternating
current (AC)
2nd Direct Current (DC)
Explain 1st :- Alternating current
means that all times the flows in change polarity, electric charge periodically
reverses it starts from "0-1" and returns to the original value
"1-0" and this cycle repeat each time and it will continue, this
cycle measure in Hertz and normally use 50-60 hertz frequency in our house,
this 50-60 hz is called frequency.
AC Current Advantages:-
Alternating current is easy to generate or transmit and has low energy losses, and other advantage that easily steps up or step down by help of transformer, and low maintenance costs of high speed motors, but this current cannot store, Only generate or use.
Explain 2nd:- Direct current flow in one
direction it has two points Negative and Positive but some costly and difficult
to generate and transmit because give much losses, but it can easily store by
help of battery or cell.
What is Resistance:-
Opposition flow of free electrons or current in any electrical circuit. Resistance discovered by “Georg Simon Ohm” in 1827 he discovered some laws relating to the strength of a current in a wire, resistance unit set on his name ‘ohm’ Resistance measured in ohm and its symbol is Greek letter “omega” (Ω) and he explain some resistance laws.
1st Law:-
Length of conductor is directly proportional to its resistance, means when any conductor length will be increase so its resistance will be increase, when length decrease resistance will be decrease.
Example:- We have two pipes first pipe is “5 foot”
and second pipe is “10 foot” if same water pressure pass through them so will
get water first from “5 foot” pipe and get after from “10 foot”, pipe so it
means length makes some resistance to water flow, when “5 foot” pipe having low
resistance and “10 foot” pipe having more resistance. Same like this,
resistance will effect on current in any wire.
2nd Law;
Area of cross section of conductor is inversely proportional to its resistance, means when any conductor Cross section area will be increase so its resistance will be increase, when cross section area is decrease resistance will be decrease.
Example:- We take same above example
that we have two pipes first pipe’s cross section are is “2 mm” and second pipe
is “5 mm” if same pressure pass through from any pipe we will get water first
from”5 mm” pipe and get after from “2 mm”, so it means cross section area
reduce resistance to water flow, because “5 mm” pipe’s having low resistance
and “2 mm” pipe having more resistance, same like this, resistance will
effected on any wire’s cross section area.
3rd Law;
Temperature:- in this case resistance involved by two method.
1- Positive
temperature co efficient
2- Negative
temperature co efficient
Temperature co efficient means, much resistance change on 1 degree
centigrade if temperature increased of any material.
Such material which resistance will increase on temperature it
called positive co efficient and which material resistance will decrease it
called negative co efficient, mostly Conductor fulfill to first point and
insulator fulfill to Second point.
4th Law;
Specific resistance this is nature of material, means if material is conductor so resistance will low if material is insulator that resistance will high, this law depended on nature of material.
There are two high resistance materials:-
1st Nichrome
wire:- This wire mostly use in Electrical Heater, Cloth pressing Iron and
Water Geyser etc
2nd Tungsten
wire:-. This wire mostly use in bulbs.
How to measure electrical current?
Electrical current measure by ”Ammeter” and it connect in series, if were connect in parallel the path become short circuit because all current pass through the ammeter instead of circuit.
How to measure electric force?
Electric force measure by volt meter, it use in parallel, if were connected in series it not work properly.
!..Some important
Electrical Measurements Si Units…!
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