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Activity for Nick Alexeev‭

Type On... Excerpt Status Date
Comment Post #293375 (overall) You must "truly appreciate [as you put it]" the time of the volunteers here. The three people who have answered your questions have decades [plural] of experience each, and their market consulting rates are in three digits of dollars per hour.
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17 days ago
Comment Post #293375 You are asking for a spot of design review. For that to start happening , you need to post. (1) Links to the component datasheets, and other reference material. Don't expect us to spend volunteer time on searching for things which you already read. (2) Post the schematic. (3) Post the layout.
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17 days ago
Edit Post #293359 Post edited:
18 days ago
Comment Post #293368 @#52987 I asked Eyal78 the same question about 4-layer board. His response here: https://electrical.codidact.com/comments/thread/10542#comment-26409 . From the description it sounds like a low speed board.
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18 days ago
Comment Post #293368 @#98019 Andy and I asked you the same question: "Why don't you want to use a 4-layer board?" Do tell us your reasons.
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19 days ago
Edit Post #293364 Post edited:
19 days ago
Edit Post #293364 Initial revision 19 days ago
Answer A: Power polygon and matching ground
> If it is important, how crucial is it that the polygon completely overlaps the ground plane beneath it? A power polygon can hang off the side a of a power plane. Complete overlap isn't crucial. > [...] how significant is it that the ground plane remains continuous and is not split by traces?...
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19 days ago
Edit Post #293272 Post edited:
about 1 month ago
Comment Post #293118 A few years ago I was hired to help with a project. Towards the end of the project of course, as is typical for war stories. The circuit had an external watchdog timer (reset supervisor IC) which was fed from the I2C clock line. The engineer who designed the board ran out of GPIO pins and decided ...
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2 months ago
Edit Post #293118 Post edited:
2 months ago
Edit Post #293008 Post edited:
3 months ago
Edit Post #293009 Post edited:
added schematic snippet
3 months ago
Edit Post #293009 Initial revision 3 months ago
Answer A: Photodiode transimpedance amplifier with single supply
synopsis Achievable by using a rail-to-rail op-amp. A small bias on the non-inverting input improves the transient response of the op-amp. That’s the second circuit in the O.P. I use such topology myself for sensing flashing light, as well as steady ambient light. TIA op-amp with non-inver...
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3 months ago
Edit Post #292909 Post edited:
3 months ago
Edit Post #292898 Post edited:
update which was posted as an answer converted into an edit of the question
3 months ago
Edit Post #292909 Post edited:
4 months ago
Edit Post #292909 Post edited:
4 months ago
Edit Post #292898 Post edited:
4 months ago
Edit Post #292909 Initial revision 4 months ago
Answer A: OPA2211 datasheet discrepancy
The 1st page of a datasheet is written by marketing. It can still give you an idea of what the chip is about, but it often contains the performance data under the best conditions. The conditions are rarely specified on the 1st page. Always check the electrical characteristics section and the cha...
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4 months ago
Edit Post #292872 Post edited:
new tags added
4 months ago
Comment Post #292527 @#56656 Are you certain that you have pollution level 1, and not 2 ? Pollution level 1 is a sealed enclosure. Pollution level 2 is a PCB in a vented enclosure under room conditions (say a motherboard in a desktop PC). Pollution level 2 is the default when you have neither aggravating factors nor ...
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5 months ago
Comment Post #292525 I doubt that these connectors are intended for scenarios where center conductor and shied are on opposite sides of basic insulation. Just like there's no IEC basic insulation in the USB or HDMI jack. What kinds of signals are you going to run through these coaxes? If you'd like further analysis on...
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5 months ago
Edit Post #292378 Question closed 6 months ago
Comment Post #292295 Welcome to EE.Codidact . Out of curiosity, which book is this circuit from?
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6 months ago
Edit Post #292295 Post edited:
6 months ago
Comment Post #292235 Let's look at your situation more broadly. Are you making a one-off for your own home use? Or it this going to be a production run? Or something more exotic?
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6 months ago
Comment Post #292235 I'd say that the laptop was certified as a system: its case, antenna, and all. If you replace the antenna with something that's not an official replacement part or an accessory released by the maker of the laptop, that would void the certification. It's possible to take FCC certified parts and some...
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6 months ago
Comment Post #292235 You're going to void the FCC certification which the original laptop had.
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6 months ago
Edit Post #292133 Initial revision 7 months ago
Answer A: Purpose of resistance between SENSE/FORCE line of power supply
> Furthermore, an amplifier symbol called "gm" is labeled as transconductor. What does it do? Transconductors are voltage-controlled current sources, but what are they doing here? The diagram looks like a voltage output power supply. I'll make a working assumption that it's voltage output power s...
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7 months ago
Comment Post #292131 Could you edit your post, and add a link to the manual (or the datasheet, or the product page), please?
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7 months ago
Comment Post #292080 Are you designing the entire system? Or are you plugging into an existing system? A lot of systems have a periodic "heartbeat" message on the CAN bus. When your PIC sees the message then it knows it's connected to CAN.
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7 months ago
Edit Post #292007 Post edited:
7 months ago
Edit Post #292007 Post edited:
7 months ago
Edit Post #292007 Initial revision 7 months ago
Answer A: STM32. What should be done in firmware for VBUS detection through a GPIO pin?
I've found a solution, and tested it. What @Olin wrote earlier holds. This is to post my code for STM32. > Does the VBUS detection have to be done in an interrupt? I've asked the ST's technical support, and they replied that it should be done in the interrupt. Here's my ISR code. / ...
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7 months ago
Comment Post #291971 Already a useful article. - You could mention that some MCUs have pins which modify how the MCU received the firmware from the ICD and runs it. -- STM32 have bootloader enable pins BOOT0 and BOOT1. Their behavior and default state varies slightly from sub-family to sub-family (it's described i...
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7 months ago
Edit Post #291935 Post edited:
8 months ago
Edit Post #291935 Post edited:
8 months ago
Edit Post #291935 Post edited:
8 months ago
Edit Post #291935 Post edited:
8 months ago
Edit Post #291935 Initial revision 8 months ago
Answer A: Are LDOs more efficient than switching regulators in very low currents?
The efficiency of the LDO is a function of the input and output voltages. $$\eta = \frac {P{out}} {P{in}} = \frac {I{out} V{out}} {I{in} V{in}}$$ $I{out} \approx I{in}$ for a series linear regulator ¹ ². Input and output currents cancel. $$\eta \approx \frac {V{out}} {V{in}}$$ In your ...
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8 months ago
Edit Post #291838 Post edited:
8 months ago
Comment Post #291833 @#53469 Nice app note. It's the answer to the question.
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8 months ago
Edit Post #291838 Initial revision 8 months ago
Answer A: Using only ceramic capacitors on an input of an SMPS - unclear advice from manufacturer
The electrolytic capacitor acts as a snubber in parallel with the ceramic capacitors. If one were to design an RC snubber to dampen the LC circuit, it would have a large capacitance (compared to the ceramic), and some series resistance. An electrolytic capacitor with some ESR is a cheap way to get ...
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8 months ago