Ohm’s law
Ohm’s law is a fundamental principle in electrical engineering that describes the relationship between electric current, voltage, and resistance.
The law states that the current passing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. Mathematically, Ohm’s law can be expressed as:
I = V / R
where I is the current in amperes, V is the voltage in volts, and R is the resistance in ohms.
In other words, if the voltage across a conductor is increased, the current through it will also increase provided the resistance remains constant. Similarly, if the resistance is increased, the current will decrease for a given voltage. Ohm’s law is useful in designing and analyzing electrical circuits, and is one of the fundamental laws in electrical engineering.
Ohm’s law states that the R in this relation is constant and independent of the current. If the resistance is not constant, the previous equation cannot be called Ohm’s law, but it can still be used as a definition of static/DC resistance. Ohm’s law is an empirical relation that accurately describes the conductivity of the vast majority of electrically conductive materials over many orders of magnitude of the current. However, some materials do not obey Ohm’s law; these are called non-ohmic.
Three definitions of Ohm’s law
Ohm’s Law defines this relationship and can be stated in three ways.
1. Applied voltage equals circuit current times the circuit resistance. The following equation is a mathematical representation of this concept. V = I x R
2. Current is equal to the applied voltage divided by the circuit resistance. The following equation is a mathematical representation of this concept. I = V / R
3. Resistance of a circuit is equal to the applied voltage divided by the circuit current. The following equation is a mathematical representation of this concept. R (or Ω) = V / I
