Log and Antilog Amplifiers Explained | Applications of Log and Antilog Amplifiers

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Log and Antilog Amplifiers Explained | Applications of Log and Antilog Amplifiers

Рет қаралды 169,478

6 жыл бұрын

In this video, the log and antilog amplifier circuits using op-amp and their applications have been discussed.
The following topics have been covered in this video:
0:22 The applications of log and antilog amplifier
2:24 Log amplifier circuit using the diode
6:48 Antilog Amplifier circuit using the diode
9:50 Log Amplifier circuit using a transistor
13:26 Antilog amplifier circuit using a transistor
16:48 Practical Log amplifier circuit (Temprature compensated Log ampliifer Circuit)
Applications of log and antilog amplifier:
The log and antilog amplifiers are very useful in the analog computer. Using these amplifiers it is possible to perform the mathematical operations like multiplication, division, and finding roots and power.
These circuits are also useful in signal compression. (For enhancing or reducing the dynamic range of the signal)
This video will be helpful to all students of science and engineering in understanding the log and antilog amplifier circuits and its usefulness in various applications.
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Пікірлер: 129

@ALLABOUTELECTRONICS 6 жыл бұрын

The timestamps for the different topics covered in the video: 0:22 The applications of log and antilog amplifier 2:24 Log amplifier circuit using the diode 6:48 Antilog Amplifier circuit using the diode 9:50 Log Amplifier circuit using a transistor 13:26 Antilog amplifier circuit using a transistor 16:48 Practical Log amplifier circuit (Temprature compensated Log ampliifer Circuit)

@infinitx1330 2 жыл бұрын

The black screen gives less stress to eyes, your explanation is crystal clear. you are an exam saver.

@Visitnepal20 5 жыл бұрын

I learned a lot. Thank you so much, sir. I have a request. Upload the design of temperature compensated Antilog amplifier if you don't mind.

@nayanbhuyan8156 3 жыл бұрын

Thank you, sir, you saved my day before the exam

@akhila5597 3 жыл бұрын

Crystal clear explanation !Please upload the design of temperature compensated Antilog amplifier.Thank you.

@chhavijaswal6342 3 жыл бұрын

Thank you soo much sir, this is what I was searching for

@iwbnwif Жыл бұрын

Thank you, I know this is an old video but I am very happy you have given us this resource for when it's needed. Will watch for the antilog version and also you difference amplifier videos now!!

@noweare1 5 жыл бұрын

Another excellent explaination. I do not see this circuit mentioned to much in the industry, maybe replaced by software?

@movax20h 5 жыл бұрын

It is still used in many applications requiring very high dynamic range and ratiometric measurements to reference, i.e. in spectrophotometry, densitometry, ultrasound measurements, RF power measurements for research and automatic gain control loops, some PID control applications, etc. It can also be used in audio and video applications (noise reduction, transmission, recording, effects, etc), where it is commonly called "compression". In some situations it is also used as a stage before low-bit ADC, as an alternative to costly high-bit ADCs.

@siddhikasingh5301 5 жыл бұрын

Why is the ideality factor for Transistor =1 ?

@dhananjaydiwate5524 3 жыл бұрын

Theory you have explained is much better. Thanks.

@srenathganesan 2 жыл бұрын

Great explanation. Please upload the design of temperature compensated Antilog amplifier. Thank you.

@vrankyrule 2 жыл бұрын

Thank-you for the lectures i have successfully cleared my backlogs

@miltonderezende7906 4 ай бұрын

In the OP AMP LOG formula the reverse current appears. However, the reverse current is not a constant value and follows a curve, albeit with a small slope. Measuring the reverse current of a diode, I found values ranging from 1 microampére to about 10 microampére. If current is not fixed, how can I enter it into the formula?

@santhiyag5387 6 жыл бұрын

Upload the deisgn of temperature compensated Antilog amplifier?

@movax20h 5 жыл бұрын

In input amplifiers just flip resistor with BJT, and make them PNP transistors. :)

@Abhishek-iq9lo 5 жыл бұрын

@@movax20h thanx bro

@Abhishek-iq9lo 5 жыл бұрын

@@movax20h AND DO I HAVE TO CAHNGE THE BJTS TOO

@Abhishek-iq9lo 5 жыл бұрын

AND WITH WHAT

@sakethsharma8299 4 жыл бұрын

@@movax20h tq soo much bruh...

@mauroalvarez6014 3 жыл бұрын

SImple and good explanation. Thank you.

@nakkalapraveen3258 5 жыл бұрын

your great work helped me in my project work .thanks a lot

@priyankasiwach5066 3 жыл бұрын

Sir,plz provide ckt for temperature comensated antilog amplifier (as it cannt be constructed just by interchanging the position of resistor and transistor)

@catnipaddict126 3 ай бұрын

Sir, please show us circuit and calculations for the Antilog Temperature Compensated Circuit, I need to cancel out the Reverse Saturation Current term

@movax20h 5 жыл бұрын

Nice video. I am trying to understand a logamp example in LTspiceXVII. It is simple partially temperature compensated circuit, but it doesn't have third differencing opamp, and one of BJTs is in transdiode config, and another one is not (shorted B and C). Additionally there is reversed diode. (Plus some caps, probably for stability control). I did run it, and adapted, and well, it does' work, but I am not sure why :D

@saranyacherry5994 4 жыл бұрын

Osum video😊very good explanation 😍my doubt is clear sir!! 🙂

@sadafriyaz1700 4 жыл бұрын

Can you please upload the vedio for temperature compensated antilog amplifier

@goofypettiger 3 жыл бұрын

That was excellent. Well done, dude!

@AmanKumar-xv6jv 4 жыл бұрын

Very nice explanation sir

@manishankarailiga347 4 жыл бұрын

When we designing log amplifier,there would case of diode going into reverse bias as bcz pside is connected to zero and nside connected to vout then the diode will be in reverse bias na then there would be no forward current.then how can that ckt is used as log amplifier.plz clear my doubt

@mayurshah9131 6 жыл бұрын

Very well explained

@pazman6856 3 ай бұрын

Was there ever a video made about the anti log circuit that is not temperature dependent?

@abhisheksingh_2416 4 жыл бұрын

Nice videos. Helped a lot..!! Thanks.

@catnipaddict126 3 ай бұрын

Sir, what happens if I short the base and collector of the transistors?

@Alireza10Rezaei10 2 жыл бұрын

thats great... thanks a lot.

@rhp1234 3 жыл бұрын

But why you have not considered R2/R1 of Subtractor output?

@ALLABOUTELECTRONICS 3 жыл бұрын

If the resistors R1, R2, R3, and R4 are selected properly the output of the difference amplifier will be Vb- Va. I have already explained that in the earlier video of op-amp has difference amplifier. That's why I didn't mention it here explicitly. I hope, it will clear your doubt.

@rhp1234 3 жыл бұрын

@@ALLABOUTELECTRONICS Yes sir, I understood. Thank u

@RG-ve8io 2 жыл бұрын

good question

@ndilipkumar4159 6 жыл бұрын

Sir explain compensating techniques to with stand for high transient currents for a basic op-amp using mosfet with equations?

@telugoons2292 4 жыл бұрын

Thank you for your help sir

@ambatihemasreesree6249 6 жыл бұрын

for anti log amp. our teacher has said Vo= -Is/R Ln^-1(Vi/nVt).Its really pleasure if u would explain this

@ALLABOUTELECTRONICS 6 жыл бұрын

There must have been some mistake while writing. Vo= -Is*R e^(Vin/nVt) is the correct way to represent the output of the anti-log amplifier. Please confirm with him/her once again.

@hemasreeambati9075 6 жыл бұрын

@@ALLABOUTELECTRONICS sure

@electrowizards1355 5 жыл бұрын

Sir , how temperature dependent resistor manage the thermal voltage ??????

@sKommanaLeelavathi 5 жыл бұрын

by thermisters

@AjinkyaMahajan 5 жыл бұрын

I really liked the explanation ✨✨✨✨

@smrutishah7839 6 жыл бұрын

informative

@rajaking1505 2 жыл бұрын

What is reverse saturation current value for 1n4007...???

@gireeshkumarkancharla4176 3 жыл бұрын

Respected sir, At 13:26 what is the dynamic range of circuit and how it is depending on ñ value

@ayanavasantra7870 5 жыл бұрын

Sera sir....... I love it.....

@mytube8884 2 жыл бұрын

Do you mean R5 is ptc resistor so when temperature increases VT value increases and R5 increases to adjust VT

@sagarkumarlo1975 5 жыл бұрын

Plz upload the temperature compensated antilog amplifier ckt

@chiraggarg3393 10 ай бұрын

Why in antilog amplifier a pnp transistor is used and in log amplifier a npn transistor is used??

@raghavendrabalekundri1842 5 жыл бұрын

THANK U SO MUCH SIR

@anishdas8106 6 жыл бұрын

nice sir

@nikhilsahu9039 6 жыл бұрын

aap sir ckt design bahut acche se batatte ho aise hi batate raho sir thanks sir

@nikhilsahu9039 6 жыл бұрын

sir apka email id mil sakata hai thoda designing ke bare me janana tha

@Abhishek-iq9lo 5 жыл бұрын

@@nikhilsahu9039 bhai agar mail mili ho toh mujhe bhi send kar diyo

@mjunaediqbal 5 жыл бұрын

Hello Sir, Its much informative for me but i am still confused regarding the selection of R5, please give some more explanation about R5.

@Abhishek-iq9lo 5 жыл бұрын

it is a temperature dependent resistor which changes its value as you change the T. Just like Vt(tehrmal voltage). As Vt increases linearly with temparature from the realtion Vt=kT/q, R5 will also increase hence compensating Vt. your welcome

@MM-sc9vg 4 жыл бұрын

Hey how can I linearize GP2Y0A21YK0F Ir measuring sensor with log amplifier please help

@ramgovindp6886 4 жыл бұрын

Brilliant

@mnada72 4 жыл бұрын

Did you created a video for compensated anti-log ?

@rhp1234 3 жыл бұрын

Upload practical and project based on electronics also, it will increase your subscribers and will be helpful.

@sanjusingha1714 2 жыл бұрын

Sir, jo circuit diagram 18:30 pe dikhaya jaa raha hai usme Right se 2nd circuit Differential Amplifier nahi hai. Reason:- Differentaial Amplifer mein ek capacitor inv.. Ya ek non-inv... Terminal mein series mein jarur hota hai.

@ALLABOUTELECTRONICS 2 жыл бұрын

What I meant to say is, it is the difference amplifier, which will amplify the differential input. (The difference between the two inputs). What you are saying is the differentiator, where the op-amp is used as the differentiator circuit. I hope, it will clear your doubt.

@ayadsobhan2615 4 жыл бұрын

thank you

@Gate2024IES 2 жыл бұрын

Sir, what is being written in your video in English, it is covering your formula. Because of which I can not see and I am having problem.

@ALLABOUTELECTRONICS 2 жыл бұрын

Please turn off the subtitles in the video settings.

@vinothkumarravi6663 5 жыл бұрын

Can you explain the experiment practically.....and I want set of readins.

@muhammedajmalka6605 5 жыл бұрын

Can u please show me the diagram of temperature compensated antilog amplifier

@user-np7oo3qj3q 2 жыл бұрын

❤️❤️❤️❤️

@praveenchakraborty3935 6 жыл бұрын

Nice sir

@infinitx1330 2 жыл бұрын

Good video thank you, and a correction it is pronounced as 'Divishion' not 'Divison', it is 'shion' not 'son'. Hope you get it right next time thanks.

@kartikeyak3425 2 жыл бұрын

hey, that's just his accent. It's rude pointing it out like that -_-

@infinitx1330 2 жыл бұрын

@@kartikeyak3425 No it's called proper pronunciation, it is not something you should ignore by hiding behind an accent. When he speaks hindi let him speak it well and the same for english with proper pronuncation. It's not rude.

@jeditoto3441 3 жыл бұрын

very nice video - but so what of log amplifier - this more than just an academic exercise

@priyankasiwach5066 3 жыл бұрын

Why is the ideality factor for transistor is 1?

@nishasabharwal 4 жыл бұрын

Please upload temperature compensated antilog amplifier.....please

@massimookissed1023 4 жыл бұрын

Use the circuit at 16:50 but replace the input amplifiers with the circuit from 14:06. (Swap resistor & transistor positions, and change transistor to PNP)

@SaurabhKumar-gc1ko 3 жыл бұрын

at 11:28 can someone please clarify how vout=-vbe plz

@ALLABOUTELECTRONICS 3 жыл бұрын

By applying the KVL, you can get that relation.

@mohammedsayanmc1465 5 жыл бұрын

Which transistor is used

@arthursgarage6550 2 жыл бұрын

Does this actually work? Every circuit I've seen has failed in several simulations and actual circuits, are there specific diodes or transistors that need to be used?

@ALLABOUTELECTRONICS 2 жыл бұрын

It works more perfectly when the op-amp and transistor or diode is integrated on a single chip. With external diodes and transistor, the circuit works approximately. (Accuracy of the result will be poor)

@arthursgarage6550 2 жыл бұрын

@@ALLABOUTELECTRONICS Weird, I used a LM358 and a 1N4148 diode but it didn't work, I also tried using a PN2222 transistor which didn't work either, it sort of worked when I added a resistor to power but that's it. do I need to bias the non-inverting input? If not what would you recommend I try?

@ALLABOUTELECTRONICS 2 жыл бұрын

Have you calculated the expected voltage ? And what voltage at the output you were getting ? First, just calculate the expected output voltage based on your voltage, resistor. From the data sheet, you can approximately take the value of Is. For 1N4148, around 1 nA. And calculate the output voltage. And then in actual circuit, check what you are getting. You can also use the multisim simulation.

@arthursgarage6550 2 жыл бұрын

@@ALLABOUTELECTRONICS I am using a 1Kohm resistor, so (If I did my math right) I should be getting an output voltage of about -0.36 +0.026ln(Vin) but I don't get any voltage on the output of the circuit. I get something resembling a logarithmic function when I use a transistor with a 10Kohm resistor at the base connected to power.

@arthursgarage6550 2 жыл бұрын

@@ALLABOUTELECTRONICS So I've been running a few experiments with the log amplifier circuits. The first was reversing the direction of the 1n4148 diode, this surprisingly worked, it output the logarithm of the input, however it only did it half of the cycle. The other thing that I tried was using the transistor design, this one worked but only when the base of the transistor was connected to V+

@amrishyadav9940 5 жыл бұрын

Sir can u plz provide relevant questions for better practice in pdf form...

@ALLABOUTELECTRONICS 5 жыл бұрын

I used to post the relevant question from the previous videos in the community post. Please check the comminity tab section of the channel for more questions.

@morshedulislam5639 6 жыл бұрын

please make videos about BJT and MOSFET. my semester final is knocking at the door..

@ALLABOUTELECTRONICS 6 жыл бұрын

I am going to make series of videos on analog electronics. So it will be get covered in it.

@shuvambiswas458 6 жыл бұрын

sir what will happen when we connect voltage at non inverting terminal

@ALLABOUTELECTRONICS 6 жыл бұрын

Definitely, it will not behave like a log amplifier but it will behave kind of precision half wave rectifier.

@shuvambiswas458 6 жыл бұрын

okay thanku sir

@ZETA824 2 жыл бұрын

how come V_out is equal to (-V_d) ?

@nabapankajbhuyan2129 5 жыл бұрын

Is it same as Log Domain multiplier or not?

@ALLABOUTELECTRONICS 5 жыл бұрын

Yes it will work similarly.

@praveenchakraborty3935 6 жыл бұрын

Some questions on this topic

@karthikbanyapaka3339 5 жыл бұрын

Will this work for sinusoidal inputs

@bepower2585 4 жыл бұрын

Yes but only for positive side of sinus u can add some offset

@Neeraj-ov4my 4 жыл бұрын

12:6 why we don't write eta

@anuradha407 4 жыл бұрын

12:00 y didn't mentioned ideality factor n in Ic formula

@anuradha407 4 жыл бұрын

I didn't know about ideality factor

@dhananjaydiwate5524 3 жыл бұрын

This theory is ok, but it will be ok, if you took actual values of components and showed the output, it will be better.

@sapnapandey_sash 5 жыл бұрын

I like to work with you sir

@tejasrohi2229 6 жыл бұрын

antilog ka b daal dijiyena sir

@Abhishek-iq9lo 5 жыл бұрын

Its same. U just have to replace resistors with bjts and bjts with resistors and make pnp npn and npn pnp correspondingly

@prabhakardas4261 6 жыл бұрын

when will upload the next topic of opamp

@ALLABOUTELECTRONICS 6 жыл бұрын

Many of you wanted the videos on analog electronics, particularly on the diode, transistor (BJT, MOSFET) and other topics so I am going to cover it first. The video will be most probably uploaded today.