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Test Equipment / Re: Heads up on MicSig Probe
« Last post by WattsThat on Today at 09:47:47 pm »Just grabbed one with the same deal.
Thank you very much for posting!
Thank you very much for posting!
Recent Posts
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Projects, Designs, and Technical Stuff / Re: what certification is required to sell electronic products?
« Last post by Retirednerd2020 on Today at 09:45:01 pm »Does anyone have an estimate of what this costs these days? Last time I ran a product through for safety for USA and Europe to UL60950/EN60950 (IT Equipment) using TUV as the testing agency, I believe the costs were about $30,000 for 2-3 minor variants of the same product. Changes after that for modifications after certification were in the $5,000-10,000 range. Even substituting inconsequential parts could cost quite a lot after the fact. The emissions / susceptibility testing cost added more to that but I forget the total cost.
It is essential to bear in mind that changes will cost you and to plan ahead with potential second source components. Don't run it through agencies until you have thoroughly functional/ and pre-safety-tested yourself. It is generally easier and cheaper to get it done up front vs. piece-meal later on.
It is essential to bear in mind that changes will cost you and to plan ahead with potential second source components. Don't run it through agencies until you have thoroughly functional/ and pre-safety-tested yourself. It is generally easier and cheaper to get it done up front vs. piece-meal later on.
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Open Source Hardware / Re: ESP32 Ethernet, Wi-Fi & Serial Gateway
« Last post by selcuk on Today at 09:44:11 pm »
Looks nice!
Some questions/comments:
- choosing to use the bare ESP32 IC is a bold move, because that means you have to seek regulatory certification yourself for the radios. (One of the big advantages of using an ESP32 module is that they’re already certified worldwide.)
- why USB mini-B and not USB-C?
- what are the two different Ethernet port versions?
- the datasheet has a typo, the RTC crystal should be 32.768kHz, not 32.758kHz.
Thank you for your comments and pointing out the error in the datasheet.
I used micro USB since it is cheaper, and I have lots of them at my office. But USB-C is a good idea. I can use it when I make a second revision.
There are two boards with the same functionality in this project. One has components for a temperature range of -40 to +85 °C. That one has a more expensive Ethernet connector. The other board design is for 0 to 70 °C and I used a lower priced connector.
You are right about the certification, but I personally don't prefer to use modules instead of bare MCUs. Even I used it, I would need to get a certification for the whole product. I can say that the ESP32 Ethernet modules on the market are very susceptible to both radiated and transient emissions. The main goal of this design was having a robust ESP32 Ethernet module to use for my projects.
And there is another purpose. After I decided to do an open source design, I wanted to contribute more by not using a module and by doing the PCB antenna design from scratch for this board. ESP32 modules' PCB antennas are not that good, and I thought there was a room for an improvement.
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General Technical Chat / Re: Post a picture of a cat!
« Last post by NiHaoMike on Today at 09:39:36 pm »5
Projects, Designs, and Technical Stuff / Re: DIY-SMU Project
« Last post by SebastianH on Today at 09:37:26 pm »Most OPA140/145 in his design either are configured as buffers or do have a capacitor from out to in-. All exceptions that I have found:
1. the integrator/compensator has an R in series with the capacitor
2. the reference inverter/buffer (there the OPA140/145 might not be the best choice anyway)
3. current sensing (schematics R3, U21.1)
4. voltage sensing (schematics R3, U19.1)
Imho only 3. and 4. are of concern:
3. In this thread we discussed a different approach using a three-opamp instrumentation amplifier, eliminating the 100k issue. It has been a while - I don't know whether I did a simulation to analyze stability "in circuit". Certainly did a simulation for the instrument amplifier itself (result 2x 10pF .. 22pF for the difference amplifier).
4. Might be worth adding footprints for two capacitors (likely something like 2x 10pF .. 22pF as well).
1. the integrator/compensator has an R in series with the capacitor
2. the reference inverter/buffer (there the OPA140/145 might not be the best choice anyway)
3. current sensing (schematics R3, U21.1)
4. voltage sensing (schematics R3, U19.1)
Imho only 3. and 4. are of concern:
3. In this thread we discussed a different approach using a three-opamp instrumentation amplifier, eliminating the 100k issue. It has been a while - I don't know whether I did a simulation to analyze stability "in circuit". Certainly did a simulation for the instrument amplifier itself (result 2x 10pF .. 22pF for the difference amplifier).
4. Might be worth adding footprints for two capacitors (likely something like 2x 10pF .. 22pF as well).
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Other Equipment & Products / Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Last post by DavidAlfa on Today at 09:33:08 pm »Always post pictures,or no help!
Search "245" here: https://www.eevblog.com/forum/reviews/stm32-oled-digital-soldering-station-for-t12-handle/
Search "245" here: https://www.eevblog.com/forum/reviews/stm32-oled-digital-soldering-station-for-t12-handle/
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Beginners / Re: What function generator, that does a bit more than just a simple signal
« Last post by radiolistener on Today at 09:32:01 pm »It also supports arbitrary waveforms uploaded from a computer. Never tried that, either, so I'm not sure what software is available and if it's any good.
It is possible that it is compatible with PSG9080. If so, then can be used my tool: https://github.com/qrp73/PSG9080_ARB
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Projects, Designs, and Technical Stuff / Re: Vacuum Fluorescent Display Driver
« Last post by floobydust on Today at 09:31:56 pm »Look if the VFD filament wires are glowing dim orange. Recheck your soldering, especially to the (filament) pins which are on the far outside ends of the tube.
I'm not clear what it is doing now.
I'm not clear what it is doing now.
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Buy/Sell/Wanted / Re: FS: Siglent SDS1104X-E
« Last post by mmora on Today at 09:25:05 pm »It is SOLD now (not in this forum, however, but via the local app).
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Other Equipment & Products / Re: T12 STM32 V2.1S Soldering Station Controller - schematic etc.
« Last post by geonicz on Today at 09:23:15 pm »Hi everyone!
Hope someone can help me with my trouble. I've just bought one more pcb from China, cause they're like leftovers from the past and cost much less than other versions without docs, with strange controllers onboard and without ability to flash devidAlfa's firmware. So, it was a good looking choice. I had one for long enough and deividAlfa's firmware forced me buy one more. Mostly for c245 and c210 tips. It's called the "2.1S original pcb" sometimes. At least in dreamcat4's project. Here is a photo of this controller. Schematics is also there. I've flashed firmware, connected t12 tip, connected c210 tip. Everything works fine. But the problem is with the c245 tip. I don't know how to connect it to this controller correctly to work with this firmware. Don't know which traces should be cut and which resistors where should be added to support c245 tips. Maybe someone can help with it?
Hope someone can help me with my trouble. I've just bought one more pcb from China, cause they're like leftovers from the past and cost much less than other versions without docs, with strange controllers onboard and without ability to flash devidAlfa's firmware. So, it was a good looking choice. I had one for long enough and deividAlfa's firmware forced me buy one more. Mostly for c245 and c210 tips. It's called the "2.1S original pcb" sometimes. At least in dreamcat4's project. Here is a photo of this controller. Schematics is also there. I've flashed firmware, connected t12 tip, connected c210 tip. Everything works fine. But the problem is with the c245 tip. I don't know how to connect it to this controller correctly to work with this firmware. Don't know which traces should be cut and which resistors where should be added to support c245 tips. Maybe someone can help with it?