Timeline for Adding multiple differential signal
Current License: CC BY-SA 4.0
18 events
| when toggle format | what | by | license | comment | |
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| May 10, 2023 at 3:14 | comment | added | Dave X | The notes at nhn.ou.edu/~bumm/ELAB/Lect_Notes/Op_Amps_v1_2_2.html have different gains -- for the inverting side, its just Rf/Ra, but for the non-inverting side, it's Rf/(Ra||Rb||Rc||Ry) Quote: "An important observation is that multiple inputs into the non-inverting side of the op amp do not sum in the simple way that they do for inverting inputs. Thus the summing amplifier that we listed as a basic building block does not have a non-inverting analog! (If we need a non-inverted sum, we just follow the summing amplifier with a unity gain inverting amplifier.)" | |
| May 10, 2023 at 2:57 | comment | added | Dave X | Broken link. // How do you calculate the gain? Is the gain Rf/Ry for each of the V_1..n and V_a..n? | |
| Dec 15, 2018 at 13:55 | comment | added | Transistor | "But they are series with resistor!" No they are not. You have -OUT-A short-circuited to +OUT B. | |
| Dec 15, 2018 at 12:35 | comment | added | mohammadsdtmnd | But they are series with resistor! I have other question that I will be happy if you can tell your opinion about: electronics.stackexchange.com/questions/412363/… | |
| Dec 14, 2018 at 15:29 | comment | added | Transistor | I explained that in my comment above. What will happen if one output is at 3 V and the other at 2 V and you connect them both? | |
| Dec 14, 2018 at 14:51 | comment | added | mohammadsdtmnd | @Transistor I want to document somewhere that we can't series in this way, exactly I must write why we can't? | |
| Dec 14, 2018 at 14:34 | comment | added | Transistor | No, you can't series connect the outputs. Each output is driven to a voltage. By connecting them as you have shown in your update you are short-circuiting the outputs to each other. It might work if each output was on an isolated circuit but this will be far more complex than the op-amps you are scared of. | |
| Dec 14, 2018 at 13:57 | comment | added | mohammadsdtmnd | @EdgarBrown You mean: making OpAmps without transistors is possible! what is it's relation to my question??!?!? | |
| Dec 14, 2018 at 13:48 | comment | added | mohammadsdtmnd | @EdgarBrown Whats meaning: "Making OpAmps out of transistors"?!?!? I have asked about making differential OpAmps in series. | |
| Dec 14, 2018 at 13:44 | comment | added | mohammadsdtmnd | @Transistor The question has been updated. | |
| Dec 14, 2018 at 13:33 | comment | added | Transistor | @mo: Please edit your question to add a schematic of "making sources series" and explain how you think this would make it easier. | |
| Dec 14, 2018 at 13:32 | comment | added | Edgar Brown | I object!!!! There is absolutely nothing wrong with making op Amos out of transistors!!! Particularly if you are an IC designer. | |
| Dec 14, 2018 at 13:21 | comment | added | mohammadsdtmnd | What's about making sources series? isn't that easier? | |
| Nov 25, 2018 at 12:52 | comment | added | Transistor | They are the input bias or leakage currents which will be specified in your chosen op-amp datasheet. | |
| Nov 25, 2018 at 11:17 | comment | added | mohammadsdtmnd | What are bias currents in this image? | |
| Nov 25, 2018 at 11:16 | vote | accept | mohammadsdtmnd | ||
| Nov 24, 2018 at 16:13 | comment | added | mohammadsdtmnd | It's nice but, I think, though it's only correct way, routing on PCB for 4 differential channel is really complicated. Also I searched your key-word "differential amplifier", and I've found lots of thing like the picture you posted, thanks. do u have any sug. for it's routing problem? | |
| Nov 24, 2018 at 8:16 | history | answered | Transistor | CC BY-SA 4.0 |