@@eie_for_you i so get the whole paradigm. I used to repair aviation systems like, radios (Colins 618T), navigation devices and heaps of Test and Measuring gear (you might have called it a PMEL or Cal Lab in the day)
@@thecasualengineer99 And it was really cool doing that stuff, too! Our "uniform" which we wore over top of our olive drab fatigues was a white lab coat. Yep ... those were the days, my friend. 🙂
There are a couple of things to consider ... first, the frequency range of the nanoVNA. Mine only goes down to 50 KHz. Is this low enough for what you are looking for? Second is the input limitations of the nanoVNA. Here is a link to measuring the frequency response of an amplifier using a nanoVNA that might help. th-cam.com/video/IGpF9B4ZlT4/w-d-xo.html Regarding the impedance ... I've uploaded a video that will answer that question for lower frequencies. It will be going public on October 2. The one following that will be with the nanoVNA to measure the complex input impedance of a device or circuit.🙂
👍Dear sir Thank you for the video. if my (R1=1ohms R2=100ohms gain=100),(R1=1k R2=100k gain=100),(R1=10k R2=1000k gain=100). all are same gain=100. can we use any of this combination?. if not which combination we have to use?. And what way this will affect circuit?.(input impedance and output impedance?)
I am assuming you are talking about an inverting amplifier. A non-inverting would have a gain of 101. If I were aiming at a gain of 100, I'd break it up into two stages of Av=10...just say'n. Now to the values. In a basic sense, the input impedance = the gain resistor value. So, if the gain resistor is 10K, then the input impedance will be 10K. What this means is that the combination of resistor values you choose is first dictated by the desired input impedance, then calculate the needed feedback resistor from that. With that said, any combination that you gave would work just fine assuming that your input impedance is acceptable to your application. Output impedance is determined by the op amp itself and is virtually unaffected by the choices of R1 and R2. This value can be found in one form or another in the datasheet. You might have to back calculate it from data given. Hope this helps. 🙂
@@eie_for_you Just one quick not of caution here ... if you take your feedback loop too low in impedance you risk it becoming lower than the op-amp's output impedance, at which point it would become unstable. It's generally best to have a lower impedance output feeding a higher impedance input. This allows more efficient signal transfer and ensures that "this" stage will not destabilize the one before it. In audio, for example, typically a 300 ohm output feeds an input of 10k or higher to maximize stability.
Hitting the op-amp wall is not fun, especially when the prototypes are sitting on your workbench .... We used to plot a SOZ chart ... Safe Operating Zone for our amplifiers, showing GBP vs Design gain ... heaven forbid the two curves should touch.
@@eie_for_you I always found it particularly useful for variable gain circuits like RIAA deemphasis or tone controls. It's surprising how often RIAA curves fall outside of the GBP of common op-amps.
@@Douglas_Blake_579 Well, now I learned something from you! I knew we used pre-emphasis/de-emphasis on FM and magnetic tape recording, but I *didn't* know they did that on vinyl, too! It makes sense. Just never actually thought about it much not being an audiophile.🙂
@@eie_for_you Oh my ... that's an oldie going back to the 1950s. The RIAA equalization lets them cut smaller grooves with less chance of skipping, but it does require some pretty careful curve matching if it's going to sound right. Some RIAA pre-amps have gains of 40 and 60 db to contend with. As a service tech I did a fair stint in audio and pro-audio. I love a good sounding system but calling me an "audiophile" feels like an Insult. Some of the stuff those guys are into just baffles the hell out of me...
@@Douglas_Blake_579 That is cool that they figured all that out. After I took my record player apart in 6th grade, I never owned another turntable or records ... just cassette tapes and not a lot of them. I listened to AM radio all through High School and was quite satisfied with it. I still do not have anything worth bragging about for sound and I'm happy with what I have. I know what you mean about the self-proclaimed "audiophiles." It's right up there with nearly every show that has *any* kind of electronics or amateur radio in it. (e.g. soldering on a cell phone with a soldering gun!). You would **think** that the writers would make at least a small effort to get the facts approximating reality. Oh well ... it gives me something the chuckle at even in the most serious show. 🙂 Maybe the better term is audio engineer or audio technician for those who actually know what they are doing. I've run a LOT of sound boards and aligned complete sound systems with their equalizers (the manual method with pink noise and a signal analyzer).
Clearly others have not discovered this channel yet! You have made this very clear to me. Excellent presentation!
Thank you! ... spread the word! 🙂
I just discovered your channel and very impressed with your presentations. Clear and concise. Thank you.
You are very welcome, Dave! Welcome to the "family." 🙂
Another great video. Thanks for the clear explanations and on-screen equations.
Thank you and you are very welcome! 🙂
Thankyou. Great prezzo and info. Cheers
Glad it was helpful! :-)
2:16 oh yes, those rose glasses ideal assumptions always bit me till I recognised the limitations
Truthfully, I have been bitten by them, too. Hopefully this video will help others avoid the viper's den! 🙂
@@eie_for_you i so get the whole paradigm. I used to repair aviation systems like, radios (Colins 618T), navigation devices and heaps of Test and Measuring gear (you might have called it a PMEL or Cal Lab in the day)
@@thecasualengineer99 And it was really cool doing that stuff, too! Our "uniform" which we wore over top of our olive drab fatigues was a white lab coat. Yep ... those were the days, my friend. 🙂
Hi, what about doing this gain x frequency using a NanoVNA? Another thing I would like to know is about impedance of this amplifier. Thanks
There are a couple of things to consider ... first, the frequency range of the nanoVNA. Mine only goes down to 50 KHz. Is this low enough for what you are looking for? Second is the input limitations of the nanoVNA.
Here is a link to measuring the frequency response of an amplifier using a nanoVNA that might help.
th-cam.com/video/IGpF9B4ZlT4/w-d-xo.html
Regarding the impedance ... I've uploaded a video that will answer that question for lower frequencies. It will be going public on October 2. The one following that will be with the nanoVNA to measure the complex input impedance of a device or circuit.🙂
EXCELLENT LECTURE!A CONFUSED GORRILLA LOL!
Thanks! 🙂
👍Dear sir Thank you for the video.
if my (R1=1ohms R2=100ohms gain=100),(R1=1k R2=100k gain=100),(R1=10k R2=1000k gain=100).
all are same gain=100.
can we use any of this combination?.
if not which combination we have to use?.
And what way this will affect circuit?.(input impedance and output impedance?)
I am assuming you are talking about an inverting amplifier. A non-inverting would have a gain of 101.
If I were aiming at a gain of 100, I'd break it up into two stages of Av=10...just say'n.
Now to the values. In a basic sense, the input impedance = the gain resistor value. So, if the gain resistor is 10K, then the input impedance will be 10K. What this means is that the combination of resistor values you choose is first dictated by the desired input impedance, then calculate the needed feedback resistor from that.
With that said, any combination that you gave would work just fine assuming that your input impedance is acceptable to your application.
Output impedance is determined by the op amp itself and is virtually unaffected by the choices of R1 and R2. This value can be found in one form or another in the datasheet. You might have to back calculate it from data given.
Hope this helps. 🙂
Thank you sir.@@eie_for_you
@@ornithopterindia You are very welcome! 🙂
@@eie_for_you
Just one quick not of caution here ... if you take your feedback loop too low in impedance you risk it becoming lower than the op-amp's output impedance, at which point it would become unstable.
It's generally best to have a lower impedance output feeding a higher impedance input. This allows more efficient signal transfer and ensures that "this" stage will not destabilize the one before it. In audio, for example, typically a 300 ohm output feeds an input of 10k or higher to maximize stability.
@@Douglas_Blake_579 Very, very good point!
Hitting the op-amp wall is not fun, especially when the prototypes are sitting on your workbench .... We used to plot a SOZ chart ... Safe Operating Zone for our amplifiers, showing GBP vs Design gain ... heaven forbid the two curves should touch.
That is a cool idea and relatively easy to do, too. :-)
@@eie_for_you
I always found it particularly useful for variable gain circuits like RIAA deemphasis or tone controls. It's surprising how often RIAA curves fall outside of the GBP of common op-amps.
@@Douglas_Blake_579 Well, now I learned something from you! I knew we used pre-emphasis/de-emphasis on FM and magnetic tape recording, but I *didn't* know they did that on vinyl, too! It makes sense. Just never actually thought about it much not being an audiophile.🙂
@@eie_for_you
Oh my ... that's an oldie going back to the 1950s. The RIAA equalization lets them cut smaller grooves with less chance of skipping, but it does require some pretty careful curve matching if it's going to sound right. Some RIAA pre-amps have gains of 40 and 60 db to contend with.
As a service tech I did a fair stint in audio and pro-audio. I love a good sounding system but calling me an "audiophile" feels like an Insult. Some of the stuff those guys are into just baffles the hell out of me...
@@Douglas_Blake_579 That is cool that they figured all that out. After I took my record player apart in 6th grade, I never owned another turntable or records ... just cassette tapes and not a lot of them. I listened to AM radio all through High School and was quite satisfied with it. I still do not have anything worth bragging about for sound and I'm happy with what I have.
I know what you mean about the self-proclaimed "audiophiles." It's right up there with nearly every show that has *any* kind of electronics or amateur radio in it. (e.g. soldering on a cell phone with a soldering gun!). You would **think** that the writers would make at least a small effort to get the facts approximating reality. Oh well ... it gives me something the chuckle at even in the most serious show. 🙂
Maybe the better term is audio engineer or audio technician for those who actually know what they are doing.
I've run a LOT of sound boards and aligned complete sound systems with their equalizers (the manual method with pink noise and a signal analyzer).