Ohm’s Law deals with the relationship between voltage and current in an ideal conductor. This relationship states that: the potential difference (voltage) across an ideal conductor is proportional to the current through it. The constant of proportionality is called the “resistance”, R.
For Example, if we are given voltage through a component and resistor of that component, we can find current through it.
We can calculate the amount of current flowing through the resistor, likewise in this case.
Applying Ohm’s Law:
On, Putting Values:
Hence we get value of Current 1 Ampere
When you will be building a circuit to blink an LED using Arduino, or Glowing LED you will need this concept.
In this image, you can see voltage below resistance is given to be 3 V. We can calculate the value of resistance.
As max current req by Led is 20 mA.
As current is in milliamps.
Kirchhoff’s Voltage Law
Do you wonder how were those values 2 V and 3 V were written? That was possible with the help of Kirchhoff’s Voltage Law. What does that state?
It states that the total voltage around a closed loop must be zero.
How to apply Kirchhoff’s Voltage Law?
There is a sign convention (if we go from lower potential to higher potential then it takes + ve sign).
Now again coming back to question how do I get that 2 V and 3 V potential values.
First of all that 2 V is the value required by LED (LED can get a maximum of 2 V across it), we get that 3 V by applying Kirchhoff’s Voltage Law:
As the current required by LED is 20 mA.
After putting the value of current we get the value of resistance as 250 Ω.