Image 1 — [Schematic Review Request] STM32 based, Isolated PCB
Image 2 — [Schematic Review Request] STM32 based, Isolated PCB
Image 3 — [Schematic Review Request] STM32 based, Isolated PCB

[Schematic Review Request] STM32 based, Isolated PCB

Hi all, hope you're doing well. I'm a student, awefully inexperienced, and I'd really appreciate a professional set of eyes on this. I plan to post two more updates after taking in advice and be done with this within next 2 days.

The board takes RS485, a 0-10V input and a 4-20mA input from outside. It outputs a +24V-or-open discrete signal, a 0-24V output at up to 1A, and a switchable resistance across two terminals. The 1A is transient only, not continuous. STM32G474, 4-layer planned. Schematic only, no layout yet.

I've assumed you won't have time to open datasheets, so take it as given that per-component current and voltage ratings have been checked. My real questions are more fundamental:

  1. Will this circuit work at all? That's honestly my main worry.
  2. Are any of these blocks more complicated than they need to be? If something here has a standard, simpler solution I don't know about, I'd love to hear it. This is extremely important, i am out of ideas. Anything that doesn't break isolation and simplifies my desing would make my day.
  3. Is anything redundant, or doing a job something else already does?

I used an external SPI ADC instead of the MCU's own ADC, because the MCU sits on the isolated ground and I don't think an ADC pin can read a divider referenced to the other ground without shorting the isolation. And for the 0-24V output I ended up with an op-amp driving a BJT inside the feedback loop, because I couldn't find another way to get a controlled 0-24V while supplying 1A peaks. If there's a better standard approach to either, please tell me. I plan to do both debugging and uploading using STM by using boot and reset bottons.

I also have very no idea how to approach the PCB layout for this, especially the two ground regions, so any pointers there would help a lot.

Sorry if anything is unclear. This is my second or third PCB and by far the most complex thing I've attempted.

u/OkAlternative7705 — 5 days ago

Astranis Internship interviews

Hi, I was wondering if anyone can help me prep for Astranis intern interviews. From what i read online, there first round is technical and basics. second round is with hiring manager. Is that round too tehcnical and resume focused or basics? I got no idea. Never got interveiws by hiring manager before. I can prepare for first round easily. Second idk.

Non-software engineer people who interviewed with them, can you walk me through the experience? I wanna get this one for fall cause i got nothing esle to do. No classes i can take until winter.
Thanks

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u/OkAlternative7705 — 20 days ago

My chrome has activity that i never did, trying to confirm what happened plz help

Used AI to write a summary cause i have been messing with what really happened for some time now, apologize if anyone finds it annoying.

Throwing this out for a sanity check because I've been digging and want other eyes on it.

This morning I was at work, ~40 min from home. My personal Windows laptop was at home, left open and logged in (I never lock it — I know, I know). While I was gone, activity happened on it that I didn't do.

Here's the timeline I reconstructed from Chrome history (all local, on the laptop):

  • ~9:48–9:50 AM — someone browsed through my email (Gmail website, not the app — I only ever use the app on my phone, so this wasn't me on mobile)
  • ~9:52 AM — opened my Reddit account settings
  • ~9:53 AM — opened a sensitive personal document in my email (TAX DOCUMENTS through my email)
  • ~9:53–9:54 AM — Googled my brokerage, went to the login page, attempted a login
  • The brokerage blocked the login with a 2FA challenge that pushed to my phone; it got denied, so they did NOT get in

What I've checked so far:

  • Google account device activity shows all my normal devices, plus one Windows session listed only as "United States" (vague location, no city) — everything else pins to my actual city
  • Windows Event Viewer, Security log: I filtered for logon (4624), lock/unlock (4800/4801/4802/4803) between 9:40–10:20 AM. No events at all in that window. Nearest logon events are hours later.

My family refuses they used it, I got no clue, can an online virus do this? can this be done through terminal claude i got. sorry not a tech person and really confused. I just use my laptop for chrome thats all.

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u/OkAlternative7705 — 24 days ago
▲ 14 r/claude

F**K these new changes to how claude talks

This shit is so frustrating, it just argues with me forever, i tell it basic to basic stuff and it will still find a way to argure. I just said, i am sending 1A current through 5A Isat inductor and it stopped me and said use a bigger one. I can say, I wanna vote and it will still aruge. AND TO FUCKIGN TOP IT ALL OFF I CALL IT BITCH AND IT STOPS RESPONDING TO ME, YOU ARE NOT MY FUCKING GF. I JUST WANT A REFUND. PAYMENT ALREADY WENT THROUGH ELSE I WOULD HAVE SWTICHED TO GPT ALREADY

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u/OkAlternative7705 — 24 days ago
▲ 3 r/ECE

Power electronics intern interview prep

Need help prepping for an internship interview. It's for a power electronics intern role, and the company supposedly gives very tough interviews, even for undergrad students.

I can mathematically solve for ripple and other quantities for:
Buck, Boost, Buck-boost, SEPIC converters, rectifiers, inverters, transformers and their shapes, etc.

Basic knowledge (no mathematical derivation done in the past) of:
LCC, LLC, parallel capacitor, series capacitor, etc. resonant converters

Control systems:
Peak and average current control loops, voltage control.

I am currently working hands-on Multiphase converters, Trans-Inductor Voltage Regulators (TLVR BUCK CONVERTER)

I don't know if I should look more into inverter control systems like Clarke and Park transformations, or if I should maybe learn the whole mathematical framework for resonant converters.

What type of questions can I expect? Will they ask me to analyze all the converters? Or expect me to do PCB-level stuff? Control stuff? I don't know, I can't analyze a TLVR on the spot, although I have read papers that do it and have even done it in the past.

I need to pass this interview badly because I need the experience and am desperate. Any tips would help, this is for a defense/space company.

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u/OkAlternative7705 — 1 month ago

Not much to do at internship and my mentor knows it

Hey everyone,

After 200 apps, I landed a part-time ($25/hr, 20 hrs/wk) internship at an S&P 500 company. I graduate next year. My location has zero electrical engineers, so I report to a Product Engineer (PE).

The interview asked about semiconductor physics and the JD required C++/Python, so I expected skilled technical work. Instead, it’s been a month and I’ve done jack shit. I wired a PCB and helped test a control panel (which had a wrong light configuration we had to troubleshoot). All of it could’ve been done in 1–2 weeks max. Since PCB design is outsourced, there’s no design work for me.

To his credit, my mentor tries. He gave me "learning tasks" like sourcing a 40-component list and writing testing criteria. EVERYONE here is an absolute angel always nice. Really really nice , but I feel useless collecting a paycheck.

Today my mentor asked: "Is the work under or over what you expected?" He clearly knows I'm don’t do shit. I got nervous and just said, "Yeah, the JD mentioned i would be testing control panel," trying to not lie and not say truth and added that since I switched from a physics major 3 months ago, I'm technically still learning how engineers operate.

Main issue:

  1. Idk, I feel guilty that I am robbing these good people of their money. I have a second job and I work so hard there for 17/hour(after that have been overworking me from last 3 years), have developed back problems from that work and these people give me a desk and I still am worthless. But idk what can I even do. I ask them for work already. WTF TO DOOOOOOOO
  2. I don’t wanna get fired, I mean yeah I am useless but I always almost every other day ask for tasks. The tasks I am given I give it my time, even do them in my personal time, so it’s their issue that they hired someone they couldn’t assign much work too.
  3. Do other internships contact previous internship coworkers? Cause I am applying for fall now, and idk if it’s a norm for them to ask previous internships about how I did.

in terms of resume, even though I didn’t design the PCB I was gonna put experience working with communication protocols such as I2C, UART. since I did technically work on something using them. so technically I can still put things on resume. Also PCB was well designed to I try to learn from it.

Note: used ai to rewrite it in shorter form since original was too big, it’s still too large of a text but ig I wanted to let this thing out of me, it’s been bugging me for weeks now.

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u/OkAlternative7705 — 1 month ago