 Hello friends, I hope you all are doing great. In today’s tutorial, we will discuss What is Thevenin’s Theorem. There are a lot of techniques to solve complicated circuitries such as KCL and KVL. In-circuit terminology, this theorem permits any single port (The port is a pair of points which link any circuitry with the other circuits) system to transform into such circuitry which has one resistor and a single source. This method also works for the alternating current (AC) circuitries which have resistive and reactance impedances. It displays that this formula is work for (alternating current) AC circuits if these circuits have impedances instead of resistance.

This theorem was created by the French Engineer, who was specialized in telegraph engineering. In 1882 when Kerchoif’s Laws were very famous to solve circuits but these laws were difficult to implement for complex circuits. To solve complex circuits Thevenin gave his famous law which makes complicated circuits very easy to solve. In today’s post, we will have a look at its equation, example circuits, working, and applications.  So, let’s get started with a What is Thevenin’s Theorem.

#### What is Thevenin’s Theorem

• Thevenin Theorem stated that the circuitry which has many resistors and voltage sources can be transformed into such circuitry which has one resistance and single source.

#### Why we use Thevenin Theorem?

• The most complex systems of circuits have some non-variable components and some have variable.
• The suitable example for this is our house wiring circuitry which is joined with the different loading devices like motors, fans or some lighting.
• If some time in special cases we want to find current and voltage values at every component of house wiring. It will take time and will be very difficult to find the electrical parameters of every element.
• To reduce these difficult calculations, a resultant circuitry of house wiring is created so that we can easily find the parameters and analysis of circuitry become easy.
• This equivalent circuitry which we make to reduce our calculation easy is called Thevenin equivalent circuitry.

#### Working of Thevenin’s Theorem

Step 1:

• In given circuit diagram we can see that forty-ohm resistance, which linked with the points A and D eliminate this resistance and all voltage sources in the circuit.
• After this, we will develop a circuitry which has only 2 resistances in the circuit.
• Now we calculate the value of Thevenin resistance (R), R1 and R2 are parallel to each other.

Rt = (R1 x R2)/(R1 + R2) = (20 x 10)/(20+10) = 6.67 ohm

Step 2:

• In this step we will add, removed voltage sources to find the value of thevenin voltage.
•  In the given diagram, we can use ohm law to find the value of the current flowing in this circuitry.

I= V/R = (20v-10v)/(20ohm + 10 ohm) = 0.33A

• Now we find the value of voltage.

VAB = 20 – (20 ohm x 0.33A) = 13.33 V

VAB = 10 + (10 ohm x 0.33A) = 13.33 V

Step 3:

• Now we have our Thevenin Resistance and Voltage we can put our Thevenin equivalent circuit together with our original load resistor as shown below.
• As we have found resistance and voltage values, now we find the value of current the circuit for the third step is shown in the given diagram.
•  We use ohm’s law to measure the value of the current.

#### Limitations of Thevenin Theorem

• These are some limitations of Thevenin Theorem, you must keep in mind while working on the different circuitries.
• This theorem is only appropriate for such circuitry which has linear elements like a resistor, capacitor, etc. It will not work for such circuitries which has the diodes, transistors these are not linear components.
• It also not work for the uni-lateral systems.
• It also not work for such circuit which has magnetic linking among the load and the circuitry which has to convert into the Thevenin circuitry.

#### Applications of Thevenin’s Theorem

• These are some applications of Thevenin Theorem.
• This rule is applied to such circuitries in which load resistance varies, after some time it necessary to measure the value of resistance, Thevenin theorem is best for this circuitry to find the value of current and voltage.

It is the detailed article on the Thevenin Theorem. If you have any question about it ask in comments. Thanks for reading. Take care until the next tutorial.