Ohm's Law

Ohms Law

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Ohm is very small unit but it is very important for electronics

Ohm is the unit of resistance

In our previous video we discussed about the resistance

To clear the resistance topic we must understand that where we can find resistance and practically what is the resistance

In our previous video we saw that

Resistor is a passive component; it is only theoretically we studied

But practically everything has own resistance and it is also important for conduction also

Yes

Resistance is also important for conduction

How ?

Ok let’s see

Just take a small piece of wire and check its resistance and take another long piece of wire and also check it’s resistance you will get some small resistance value in small piece of wire and large resistance value on long piece of wire in comparison with small piece

But a wire can conduct electricity even resistance is present in the wire

You can just do this through multimeter

My motive is only that you should understand everything has its own resistance which opposes the flow of current to the some extent

Ok

Now we have to come on our topic Ohm’s law

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

 I = V / R

where I is the current through the conductor in units of amperes, V is the voltage measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the R in this relation is constant, independent of the current

it is the symbol of ohm

The law was named after the German physicist Georg Ohm, who, in a treatise published in 1827,

For understanding the ohms law equations this is very important to remember this triangle

To clear more this triangle

1^st if we have to calculate voltage of any given circuit than your formula will be

your formula will be

V = I X R

2^nd if we have to calculate Current of any given circuit than your formula will be

your formula will be

I = V / R

3^nd if we have to calculate Resistance of any given circuit than your formula will be

your formula will be

R = V / I

For example

Here we have to calculate resistance value for this circuit

1^st observe what you have to require for calculating the resistance

Formula :-  R = V / I

Here we required the data of green LED

Suppose green led requires = 3 volt and 0.10 A current

For calculating resistance

Here we have voltage (v = 9-3 = 6 v)

Current = 0.10 ampere

R = 6/0.10 = 60 ohm

Here we calculated resistance value 60 ohm

But practically we have to know that which watt of resistance is used here because resistors are categorized with 1 / 4 watt (quarter watt), 1 / 2 watt (half watt), 1 watt (one watt) as on

we know that unit of power is watt

Power = volt X ampere

Here we have = 9 volt supply and 0.10 ampere current

Power = 0.9 watt

Approx 1 watt

And 1 to 25 watt requires (1 / 4 watt resistor)

26 to 50 watt requires ( 1 / 2 watt resistor ) as on

This is the basic tutorial about ohms law and their calculations 

Thank you