Ohm's Law

Ohm’s Law

Ohm’s Law is probably one of the most well-known laws in electricity and physics. For students in electronics, Ohm’s law is as important as Einstein’s Relativity equation (E = mc²) is for physicists.

George Simon Ohm, a German physicist, derived a relationship between electric current and potential difference in 1828 and this came to be known as Ohms’s Law. So, let us look at the law and why is it this important.

What is Ohm’s Law?

Ohm’s Law states that the current flowing through a conductor is directly proportional to the potential difference applied across its ends, provided the temperature and other physical conditions remain unchanged. Mathematically it can be represented as,

V ∝ I

V = IR

V is the potential difference (volts(V))
I is the current (Amperes)
R is the resistance(Ohms)

Ohms Law Graph


There are a lot of applications of Ohm’s law and a lot of them can be seen daily life as well. Let us look at few of them

  1. The fan regulators is a good example of a daily life object which uses this law
  2. In mainly dc ammeter and other dc measuring instruments shunt is used to divert current. The law is used in this as well.
  3. It is also used to maintain the desired voltage drop across the electronic components.
  4. In theory, Ohm’s law is used to derive a lot of other laws including Joule’s Law of Heating

The list goes on.


As every theory and every law has some limitations or drawbacks, even Ohm’s law also have some

  1. This law is applicable for metals only and that too at a constant temperature only.
  2. It is not applicable for semiconductors devices like diodes, transistors, etc, and insulators.
  3. The change in other physical conditions like pressure etc also can make the law to fail
An Experiment To Prove the Law

So, that was a glimpse of this important law with some basic information.

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