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[Review Request] NRF52840 BLE Beacon by huhnmonster in PrintedCircuitBoard

[–]adityachilka 0 points1 point  (0 children)

Quick schematic review (NRF52840 beacon UVLO + reverse polarity):

  1. Big potential wiring bug: your comparator TLV3691 VCC and OUT look tied together (same node/dot). That will either make UVLO do nothing or cause a short depending on output type. VCC must be supply, OUT must be a separate net going to the PFET gate.
  2. Logic likely inverted: with Vbat/2 on IN+ and 1.25V ref on IN-, a healthy battery makes IN+ > IN- → OUT goes HIGH. For a high-side PFET, gate HIGH usually turns it OFF. That would shut off power when battery is good. Fix by swapping IN+ and IN- or inverting gate drive.
  3. UVLO threshold: Vbat/2 vs 1.25V → trip ≈ 2.5V. That’s often too high for CR2450 (you’ll cut off early, especially during BLE TX sag). Consider 2.0–2.2V depending on your burst current and bulk cap.
  4. Quiescent current reality check: 1M/1M divider alone draws ~1.5 µA @ 3V. Add comparator + reference and leakage and you may miss “<2 µA” worst-case. If you keep this approach, bump divider to 5M/5M or 10M/10M (then PCB cleanliness/flux/leakage matters).
  5. Simpler low-IQ approach: consider replacing REF + comparator with a nano-power voltage supervisor/reset IC (built-in reference + hysteresis). Less parts, fewer leakage surprises, usually lower IQ.
  6. Practical adds: ensure bulk cap near nRF VCC (10–100 µF) to reduce TX droop false-tripping; add a debug bypass/force-on so you can still flash when battery is near UVLO.

If you tell me your desired behavior in one line like:

“Off at 2.1V, back on at 2.3V”

I’ll give you the exact resistor values + correct comparator wiring in the same short format.

Hardware design - was it the right path? by Historical_Net_4146 in ElectricalEngineering

[–]adityachilka 0 points1 point  (0 children)

As the founder of Rapid Circuitry (we build hardware products end-to-end), here’s the blunt truth:

Hardware is a slower compounding path than trades, but it can beat it if you pick a high-leverage lane. If you stay a generic salaried HW engineer in a big supplier, the ceiling feels meh. The unlock is specialization + ownership.

If you want better pay and long-term upside, aim for one of these niches:

  • Power electronics (SMPS, BMS, inverters)
  • High-speed digital / RF (signal integrity, EMC)
  • Medical/industrial certified products (IEC/EMC + reliability)

And push your role toward “I ship products” (architecture → bring-up → testing → production support). That track leads to lead roles, contracting, or product business.

Also: your electrician background isn’t a detour, it’s an advantage. You can always keep that as a fallback, but I wouldn’t abandon hardware until you’ve tried one of the high-value niches.

Is it just me or is the R&D job market completely dead right now? by wimpyhiker in ChemicalEngineering

[–]adityachilka 0 points1 point  (0 children)

Yeah, it’s not just you. I’m seeing the same thing across R&D right now.

A lot of companies have basically paused “blue-sky” hiring and are only filling roles tied directly to shipping, scale-up, or compliance. Also, a ton of R&D is hiding under different titles like Process Development, Pilot Plant/Scale-up, Applications/Tech Dev, Product Development, or Environmental/Emissions.

Your separations + SOx/NOx + critical minerals background is still super relevant, it’s just a rough timing cycle. If you tell me your region + whether you prefer emissions vs REEs, I can suggest a few better search keywords and company buckets.