19b - 🔴MIDSEM EXAMS: Thevenin's Theorem Problems

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19b - MIDSEM EXAMS: Thevenin's Theorem Problems #knust
In this video we are going to learn how to solve circuit problems using Thevenin's theorem.
Thevenin's theorem states that any linear circuit connected between two terminals can be replaced by a Thevenin's voltage Vth in series with a Thevenin's resistance Rth.
To find the current flowing in a resistor;
1. Remove the resistor you want to find the current through and mark the terminal
2. Find the Vth using KVL
3. Deactivate all independent sources, open circuit current sources and short circuit voltage sources and find the Rth
4. Produce the Thevenin's equivalent circuit and reconnect the resistor you removed.
5. Find the current through the resistor using the formula I = Vth/(Rth + Rl)
00:00 - Problem 1
09:43 - Problem 2
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Пікірлер: 84

@alvindry9333 5 ай бұрын

Really helpfull with my final exam, From Malaysia thank you

@SkanCityAcademy_SirJohn 5 ай бұрын

You are most welcome. Thanks so much for watching

@AnnieCali Жыл бұрын

Thank you so much! This video was very helpful. Thank you for not skipping any steps :)

@SkanCityAcademy_SirJohn Жыл бұрын

You are most welcome. Where do you watch me from?

@fatbellyb3lla 11 ай бұрын

Watching from South Africa, your videos are unbelievably helpful, please keep it up man 🫡🫡

@SkanCityAcademy_SirJohn 11 ай бұрын

That's so much B3lla

@juniorarchimedes3154 2 жыл бұрын

How I was struggling to understand this,,, but you've made it very simple for me Thank u very much boss

@SkanCityAcademy_SirJohn 2 жыл бұрын

You're most welcome

@excellencyaddiluv4753 5 ай бұрын

i find this piece very helpful, thank you very much.

@SkanCityAcademy_SirJohn 5 ай бұрын

You are most welcome and keep watching

@kalonzo-zu9tl 6 ай бұрын

Wow 🎉.... Great job... This helped me understand how to solve quite a number of problems ❤❤❤

@SkanCityAcademy_SirJohn 6 ай бұрын

Thanks so so much too.

@riyazrafique9042 7 ай бұрын

great👍 watching from India

@SkanCityAcademy_SirJohn 7 ай бұрын

Thank you so much

@user-xl2xp6yv5h 4 ай бұрын

Why we use the clockwise direction in 4:41 ? It would be a mistake if we have used the anticlockwise?

@SkanCityAcademy_SirJohn 4 ай бұрын

No please, we can equally used the anti-clockwise direction, and that is also correct, the only way we will get a wrong answer is if we use the loop containing the current source.

@megata6184 Жыл бұрын

How can the thevenin voltage be greater than the voltage source in problem 2. Is it because of the 3A current source?

@SkanCityAcademy_SirJohn Жыл бұрын

Not only that, other elements in the circuit contribute to that. And it's not strange if the thevenin's voltage is larger than the voltage source in the circuit.

@MemorizeQuranEasy 2 жыл бұрын

Great work

@SkanCityAcademy_SirJohn 2 жыл бұрын

thanks so much....

@SkanCityAcademy_SirJohn 2 жыл бұрын

thanks so much....

@user-xo1ir8ef6c Жыл бұрын

I have an inquiry on the second problem,in calculating the thevenin voltage,why wasn't the 4 ohm resistor used ? We only used the 20 ohm resistor yet the 4 ohm resistor is also in the loop in consideration.

@SkanCityAcademy_SirJohn Жыл бұрын

Because the terminal ab is now opened, there will be no current in that branch (4ohms)

@user-xo1ir8ef6c Жыл бұрын

@@SkanCityAcademy_SirJohn Thank you so much for good explanation.

@SkanCityAcademy_SirJohn Жыл бұрын

You are most welcome

@SkanCityAcademy_SirJohn Жыл бұрын

where do you watch me from?

@viwemkhothi6349 Жыл бұрын

@@SkanCityAcademy_SirJohn I still dont get it ? can we use the loop containing the 24V source ? watching from uct SA

@user-to5rz9fy1n 10 ай бұрын

In question 1 Why is the 3A current not being divided between the 2ohm and the 6 ohm resistor

@SkanCityAcademy_SirJohn 10 ай бұрын

It depends on how you assign current in the circuit. You can either distribute current from the voltage source or the current source. I used the voltage source: to say that current in both 8 and 6 is I and current coming from the right is 3A. Then current in 2 will be (I + 3). You can use the current source to say that: 3 = I + I2 that is also correct.

@godswayzottor5555 6 ай бұрын

why is it that when finding the thevenin's voltage across the circuit from the right hand side the current will not flow the 4 ohms resistor? please i will be happy with somebody can help me with the understanding.

@SkanCityAcademy_SirJohn 6 ай бұрын

Please are you aware of the steps to take when solving using thevenin's theorem? You know you are supposed to eliminate the resistor you want to find the current flowing in. When that happens you have an open circuit and current cannot flow in an open circuit.

@rosemarybwalya-cv4st Жыл бұрын

Great job

@SkanCityAcademy_SirJohn Жыл бұрын

Thanks so so much Rose

@rosemarybwalya-cv4st Жыл бұрын

@@SkanCityAcademy_SirJohn welcome ♥️

@romeladianneretita9781 Жыл бұрын

I used Nodal analysis in finding the Vth, and my answer is 10.25V. Is my answer wrong?

@SkanCityAcademy_SirJohn Жыл бұрын

Thanks for trying with a different theorem. Which of the questions did you attempt and had 10.25volts for vth

@user-ChrisB 5 ай бұрын

But please why is the (6+2)//8. I thought they were all on series?

@SkanCityAcademy_SirJohn 5 ай бұрын

Assume that there is a voltage source in between the terminals ab. Now you realize that there is the left side of the circuit and the right side. 6 and 2 are connected end to end so they are in series and the combination is connected to the same two nodes with the 8 which means that (6+2)//8

@user-my8sb3nd1g Жыл бұрын

😊

@SkanCityAcademy_SirJohn Жыл бұрын

Thanks so much for watching

@danielessence465 2 жыл бұрын

The 4 ohm resistor wasn't used why??? In calculating the Vth

@SkanCityAcademy_SirJohn 2 жыл бұрын

According to the rules, you need to remove the resistor you want to find the current flowing through

@SkanCityAcademy_SirJohn 2 жыл бұрын

That's how come, the 4ohm was removed

@yammy_yams Жыл бұрын

@@SkanCityAcademy_SirJohn i think the person is referring to the 4 ohm resistor in problem 2. I'm also confused as to why it wasn't included in finding Vth

@katlehozwezwe8548 Жыл бұрын

@@yammy_yams the 8 ohm was on open circuit therefore no current was flowin through the 4 ohm.that why it was used According to my understanding hope i make sense..

@SkanCityAcademy_SirJohn Жыл бұрын

That's correct

@Sara-mn8qf 2 жыл бұрын

why 8 ohms resistor wasn't used when calculating 4th?

@SkanCityAcademy_SirJohn 2 жыл бұрын

can you please indicate the time stamp so i can help you out?

@WilchaelAduGyamfi-lg5iv 5 ай бұрын

Where from the rth

@SkanCityAcademy_SirJohn 5 ай бұрын

What do you mean, by where from rth?

@lajuelar Жыл бұрын

Please explain in details the computation of Rth.

@SkanCityAcademy_SirJohn Жыл бұрын

It's simply the resistance that is seen between the two terminals when all sources (voltage and current sources) are deactivated

@lajuelar Жыл бұрын

@@SkanCityAcademy_SirJohn thanks . I see.

@SkanCityAcademy_SirJohn Жыл бұрын

You are most welcome

@user-gx9ty5mx2i 7 ай бұрын

why have you ignored th 4ohm resistor when finding VTh

@SkanCityAcademy_SirJohn 7 ай бұрын

When solving using Thevenins theorem, you remove the resistor you want to find the current flowing through, thats how 4 ohms was ignored when finding vth

@godswayzottor5555 6 ай бұрын

i think your explanation for that answer is wrong because we are dealing with the 8 ohm's resistor without the 4 ohm's resistor@@SkanCityAcademy_SirJohn

@user-fb1kq4ju4m Жыл бұрын

man I'm watching different parts to your videos it makes sense but the steps always confuse me its always the beginning as well, where you'd divide the voltage and then at other times you are doing a different step where you just say a number parallel to another number I'm just confused i know its me. its makes sense but if i were to do it without watching's the vid I'm just back to square one i just wish there was a specific formula to keep it the same its always different every time i watch not saying its you.

@SkanCityAcademy_SirJohn Жыл бұрын

I understand, with applied electricity, you just need to understand the fundamentals. You wouldn't have a general formula to help you solve all types of questions, because each question presents how you approach it due to the positions of the circuit element. The fundamental things, how to determine how current circulated in a circuit, relating to which resistors are in series, and parallel, which one has been shorted or open circuited and all that counts a lot

@user-fb1kq4ju4m Жыл бұрын

@@SkanCityAcademy_SirJohn that's absolutely correct i sir its just im confused at times when i see it im not able to write down and understand it untill you start wrtiting. question when you have 2 voltages sources you are solving for both I and I1? and when you have a single voltage source and a current you are solving for I including the brackets for the current? for example ( I + 3) my question is if its clockwise its I plus a number and the opposite for anti clockwise ?

@SkanCityAcademy_SirJohn Жыл бұрын

Yes, if you take any arbitrary direction, if a current moves in the same direction, then it's positive, if it moves in the opposite direction, then negative

@user-fb1kq4ju4m Жыл бұрын

@@SkanCityAcademy_SirJohn Thank you sir john you are filling in these lost puzzle pieces for me and its starting to make so much more sense

@SkanCityAcademy_SirJohn Жыл бұрын

Thanks so much

@arenegarvey9920 2 жыл бұрын

Where the 4 pass

@SkanCityAcademy_SirJohn 2 жыл бұрын

can you please come again with your question?

@dvmnace4728 2 жыл бұрын

Yes the 4 ohm resistor wasn’t used

@SkanCityAcademy_SirJohn 2 жыл бұрын

Yes, so if you want to solve any network with Thevenin's theorem, you first remove the resistor you want to find the current flowing, that's why the 4 ohm was removed

@SkanCityAcademy_SirJohn 2 жыл бұрын

Can you please come again. I didn't get it.

@SkanCityAcademy_SirJohn 2 жыл бұрын

Oh okay. I get you know. That's a great point. Thanks so much Sarah.