Electric field,Electronics etc...All of your Tutorial is best. Good explanation with initial to Application. what a tutorial series.Thank u sir.#Bangladeshi EEE student.
First and foremost, that's a killer bow-tie. Bow-ties are cool. Secondly, you just saved me a massive headache. I was struggling through this derivation all morning. Your explanation was perfect. I do have a question about this whole circuit though.
Beautiful math work out........I tried on my own and gave up. Mine was not bad but didn't get the beautiful part at the end where we can clearly see why making the two ratios R1/Rf = R3/R4 gave us Vo = Rf/R1( V2-V1 ) which is a very easy to see how this circuit is "The Difference Amplifier". I have no problem understanding the electronic but I have to go over the math a couple of times. Nice lecture. Loved it.
That's brutal lol, this is more algebra tricks than engineering so i hope it wasn't an engineering job. It's one thing finding the output in terms of the input but to get it into the final equation is just pure maths i think.
Can you get two different answers if you use the first circled equation and the second shorter one? My Rf/Ri=R3/R4=2 and my V1=-5 and V2=6. Using the longer equation I get 16V and the shorter I get 22.
@@MichelvanBiezen i used the law directly to get an unkown in Nelson james reference but it is wrong the reference used th method of node voltage and get a nother solution😅🤔
I find the calculation of vo quite complex (between minute 7 and 8 something). When I do the same calculation my way, the result is vo = v2 (R4 / (R3 + R4)) ((R1 + Rf) / R1) - v1 (Rf / R1) Sorry but it's difficult to type it down like that. Anyway, by going for that shape of formula, it's easier to see what happens if R1 = R3 and Rf = R4 on one side and R1 = R3 = Rf = R4 on the other side. But again, the end result is the same (many paths lead to the same goal...). Apart from that, you're one of the very few that can really explain how a difference amplifier really works. Thumbs up!
There are many different configurations for different purposes. We cover some of them in other videos. This is the configuration for the difference amplifier.
Would it have been a bad idea to have simply jumped into using voltage devision to solve for Vb considering no current into V+ or could this cause problems in other situations?
Use non-inverting Op-Amp (not Difference Amplifier). Av = 1+(Rf/R1). For example, to convert the output voltage of an analog temperature sensor, let's say a TMP35, to a 0-5v for an Arduino, set Av = 4 (Rf = 33k, R1 = 11k). Then, TMP35 maps very nicely to Arduino supply range. Of course, adjust gain for 3.3v system. TMP35: 25C = 0.250v and 125C = 1.25v. Op-Amp transfer function is f(x) = 4x, where x is TMP35 output voltage.
Current flow from high potential to low potential (conventional current flow). If we don't know, we just pick a direction and if we picked the wrong direction the current will come out negative.
Brilliant. My professor threw us that last equation for difference amplifier, but you actually explained how it works. Thank you a ton, my friend.
You're very welcome!
Electric field,Electronics etc...All of your Tutorial is best. Good explanation with initial to Application. what a tutorial series.Thank u sir.#Bangladeshi EEE student.
Rahman sab jeety raho
First and foremost, that's a killer bow-tie. Bow-ties are cool. Secondly, you just saved me a massive headache. I was struggling through this derivation all morning. Your explanation was perfect. I do have a question about this whole circuit though.
Beautiful math work out........I tried on my own and gave up. Mine was not bad but didn't get the beautiful part at the end where we can clearly see why making the two ratios R1/Rf = R3/R4 gave us Vo = Rf/R1( V2-V1 ) which is a very easy to see how this circuit is "The Difference Amplifier". I have no problem understanding the electronic but I have to go over the math a couple of times. Nice lecture. Loved it.
Thanks sir
best explanation ive ever seen for this topic. analog systems UD class is much easier with playlists
Glad it was helpful!
Great video! The algebra towards the end really had me stuck for a while.
Without deriving the math I had a hard time understanding opamps. Thank you very much.
Had this exact question at a job interview. Got stuck at that very last step lol.
damn i didnt know jobs ask this kind of questions :/. what job btw?
That's brutal lol, this is more algebra tricks than engineering so i hope it wasn't an engineering job. It's one thing finding the output in terms of the input but to get it into the final equation is just pure maths i think.
Thank you very much, today you have been being my hero.
Great Dr. Biezen. It is really simplified explaination. Much more simpler than my book's explaination. Best regards to you Dr.
Superb❤️ from Sri lanka🇱🇰
Glad it is helpful. Welcome to the channel.
nice explanation sir I searching for this frm a week and now I got it from your video thank u sir
best explanation ever, thank you Sir
Excellent! Thank you so much for your explanation!
thank you so much, god bless you 😇👏🙏
Thank you. Glad you found it helpful! 🙂
Thank you. Your explanation makes the topic easy to understand. What textbook do you recommend for electronics devices and op-amps.
osm sir... understood the topic clearly...thank you..
Thank you sir. You made it clear👍
Glad it helped
Thank you Michel !
Great explanation! Thanks Prof!
How do you calculate this if you add a resistor from Va to gnd ( when you want to amplify a bridge case )
Can you get two different answers if you use the first circled equation and the second shorter one? My Rf/Ri=R3/R4=2 and my V1=-5 and V2=6. Using the longer equation I get 16V and the shorter I get 22.
I have an question please we use this law only when resistance are equal? (R1=R4 and Rf=R3)
They don't have to be equal, but if you do make them equal you will have that simple relationship for Vo
@@MichelvanBiezen i used the law directly to get an unkown in Nelson james reference but it is wrong the reference used th method of node voltage and get a nother solution😅🤔
Is the setup exactly the same? Or is there a difference in the way the op amp is connected?
@@MichelvanBiezen yeh it's exactly the same
nice one
Thanks
This guy is the fucking best
Thanks prof
What did you do at 6:45 to simplify that fraction what is the story?
Can anyone explain or name what is this algebraic trick at this part?
Dividing by a fraction is the same as multiplying by its inverse. 12 / (1/2) = 12 x (2/1) = 24 or (2/1) x (12) = 12 / (1/2)
I find the calculation of vo quite complex (between minute 7 and 8 something). When I do the same calculation my way, the result is vo = v2 (R4 / (R3 + R4)) ((R1 + Rf) / R1) - v1 (Rf / R1)
Sorry but it's difficult to type it down like that. Anyway, by going for that shape of formula, it's easier to see what happens if R1 = R3 and Rf = R4 on one side and R1 = R3 = Rf = R4 on the other side.
But again, the end result is the same (many paths lead to the same goal...).
Apart from that, you're one of the very few that can really explain how a difference amplifier really works. Thumbs up!
What did you do here at @8:13 ?
We multiplied the quantity inside the parentheses by the fraction Rf/R1 and re-arranged the terms.
Thank you very much
so in op amp vb=vs is always the case ? I mean the difference between vb-va must ALWAYS be approx 0 ?
O i got it .. it just depends if it’s connected to the ground or not .. if yes the potential is 0, but always vb=va
Sir what if R3/R4 does not equal R1/RF
There are many different configurations for different purposes. We cover some of them in other videos. This is the configuration for the difference amplifier.
Would it have been a bad idea to have simply jumped into using voltage devision to solve for Vb considering no current into V+ or could this cause problems in other situations?
That should work.
How could you amplify the mV output from a thermocouple to a 1-5 volts signal using an op amp?
Use non-inverting Op-Amp (not Difference Amplifier). Av = 1+(Rf/R1). For example, to convert the output voltage of an analog temperature sensor, let's say a TMP35, to a 0-5v for an Arduino, set Av = 4 (Rf = 33k, R1 = 11k). Then, TMP35 maps very nicely to Arduino supply range. Of course, adjust gain for 3.3v system. TMP35: 25C = 0.250v and 125C = 1.25v. Op-Amp transfer function is f(x) = 4x, where x is TMP35 output voltage.
How is the direction of current across the feedback resistance determined?
Current flow from high potential to low potential (conventional current flow). If we don't know, we just pick a direction and if we picked the wrong direction the current will come out negative.
why do we use R4?
AND THATS HOW ITS DONE ! BOOM !
Prof. van Biezen, are we able to use superposition principle to derive the formula?
Any method is a valid method. Some methods are easier for certain applications than others.
:D :D :D Thank you
You are welcome. 🙂
Thank you so much
You are welcome.