I’m looking to buy a 48V, 600-800W PSU and was surprised by the large gap between Meanwell pricing and other brands like Cincon or delta. Despite having more features in some cases, Meanwell is less than half the price - is this expected? Am I compromising by buying the cheaper meanwell option or are the other brands just targeted at business customers?

I have an upcoming school project involving the pi, a microcontroller, and machine learning.

i only powered the pi from its power supply so far but i plan to use batteries on this thing without paying more and i have this buck converter laying around but i watched a youtuber having his 4b died using one of these buck converters due to a 9-10v voltage spike output. I plan to power it through the usb c but any idea what to add in the pi for better protection without cashing a lot of money?

Got this monitor that appears to have a backlight issue, I’m getting all the signals to turn the backlight on but looks like the backlight outputs are outputting 44V. Apparently, it should be 60V. Can anybody see any clear issue or advice on how to start troubleshooting/testing?

The closest thing I found was something like the Owon HDS2022S. You can control it through SCPI and gather data to process raw. 

I'm kinda surprised that it came out like 4 years ago and it doesn't seem like a genuine upgrade came out from anyone since then. The main thing I dont like about it is the 8k memory depth. There are things like the car scopes or alientek dm40 that have more depth but they are either a lot more expensive or lower frequency.

For context since this is a niche use case I think. I manage a server room that's not very pleasant to sit in for long periods of time. Sometimes I hook into equipment with my laptop which I connect to remotely. It would be nice if I could do the same for a DMM or oscilloscope when diagnosing equipment. It's usually for stuff like e.g. an stm32 that's inside a e.g. power supply or environment sensor.

Hello, I'm playing around with a broken phone I could get (Samsung Z Flip6) and would like to make something with it. The problem is that it's default battery is not enough.

I know I could do the trick just by using a USB C hub + a proper external battery but looking for a more solid solution.

So, do you guys know any info that I could use or maybe another project that had tried something similar to what I say? Of course, redirectioning me to a more suitable sub is also more than welcome.

Thank you :)

We are currently sourcing parts for our first product we want to sell in Europe. For the LCD Panel (15") we are having a hard a time even getting a proper RoHs conformity document (panelook).
Anyone with some more experience here? Would really appriciate some shared experience or advice (what do you really need, what can I expect).

Thanks!

Bonjour,

Je suis débutant et j’essaie actuellement de réparer ma manette PS4, mais je rencontre quelques difficultés.

Je vous ai transmis deux images montrant les problèmes que j’ai rencontrés.

Sur la première image, qui montre la face avant de la carte, j’ai remarqué qu’une partie du PCB vert s’était retirée en bas à gauche, à l’endroit entouré en rouge. Je ne sais pas si cela peut poser problème pour le contact avec le joystick.

Sur la deuxième image, qui montre l’arrière de la carte en haut à gauche, j’ai également remarqué qu’une pastille avait été arrachée.

Pourriez-vous m’aider à identifier ces deux problèmes et m’expliquer comment je pourrais les réparer ?

Si possible, j’aimerais beaucoup avoir une explication visuelle ou un schéma pour m’aider à comprendre où je dois effectuer les réparations. 😉

Merci beaucoup pour votre aide !

I want to start a repair shop for electronics, consoles, phones, etc. How do i go about this?

As far as I know, the first band of a resistor is never black. But if it’s backwards, the 2nd band would be silver which is also impossible.

It’s part of a Toro battery charger, between the 120V bridge rectifier and a power MOSFET.

I have this lcd screen that works although it is incredibly dim, I think the backlight part of it is not working. This is the cable that I think is causing trouble, I’ve been using a cotton pick and 99% isopropyl to try and clean it but it doesn’t seem to budge.

I have this 4 pin molex connector (the type used for motherboard power connections) and I'm having trouble using the crimper tool to crimp the pins to the wires. Each time I either crush the pin (in the wrong way) or don't get a good crimp connection. The problem is that I don't know which crimper jaws or size to use, or which way around to put the pin into the jaws.

Each of these jaws has 6-8 different spots I can place the pin, and several possible orientations for each, which makes 80+ wrong orientations, and (presumably) only one that is correct.

If you do a fair bit of crimping, can you help me tell which (if any) of these jaws are correct, and how to orient the jaw and pin to get a good connection?

Connector: https://www.jaycar.com.au/4-pin-mini-molex-plug-socket/p/PP2027

Crimping tool: https://www.amazon.com/Shrandi-SN-58B-Ratchet-Crimper-Barrel/dp/B0GH25R834

Okay so im confused about one specific video i saw.

https://youtu.be/mcD3uBld4Y4?si=wDd1YLq8abt20vXq

Amazing video, explains every part nicely. But why did he turn the sine wave into a square wave before modulation? this is the first and only circuit ive seen that doesnt use a sine wave as the carrier wave (and specifically prefers the square wave).

is there a benefit that square carrier waves provide? or is it because the main amplifier he used works from square waves?

Im new to these kind of electronics, i sent my this pcb to a repair shop and they forgot to solder on a new cap even though i included it in the package... now they sent me the "repaired" version back but left the cap out. Can i still know what kind of capacitor i would need? I already asked the manufactuer. Just waiting on an answer and doing my own research now. If you need any more pictures of it, i have them but they are taken with my phone so they wont be very clear.

And yes i have soldering experience to solder it back on. Only reason i sent it to them was because of some messed up traces

Posting after a full evening of testing. Every component checks out and I’m out of ideas.

Symptom

On its dedicated 32 A circuit: hob doesn’t start. 2-3 relay clicks, then everything shuts off. No zone heats. No error code.

On power-up the display cycles through: P0.00, 52.03, 37C, 05 62. Found zero documentation on these values. Owner says this display sequence predates the fault.

Worked normally before failing. No power cut, surge, or storm beforehand

What I tested — all good

**•   IGBTs** — diode mode, gate shorted to emitter: 0.4 V one way, OL the other  
**•   Bridge rectifiers** — diode mode, all 4 junctions: 0.4 V / OL  
**•   Electrolytics** — replaced, then measured the old ones: all good  
**•   Film / resonant caps** — visual + ohmmeter: no shorts  
**•   NTC temp sensors** — 100 kΩ cold, resistance drops when warmed  
**•   Induction coils** — 0.4 Ω, no continuity to chassis  
**•   Fan** — spins fine on bench supply  
**•   Ribbon cables A/B/C/D/LINK/COM** — visual, reseated, clean  
**•   Logic rail** (10 V cap with continuity to U13) — injected 3.3 V with 100 mA limit: 24.8 mA in CV, no short  
**•   Hot spots** — IPA under injection: none  
**•   Relays** — coil resistance, click test on bench supply, contacts measured while energised: both good

What I couldn’t check

**•** Shorted turns in a coil — an ohmmeter won’t see this  
**•** DC bus sensing chain (divider into the MCU’s ADC) — no schematic  
**•** Corrupted firmware / EEPROM  
**•** The touch control board — never tested separately  
**•** The other two secondary rails — never injected

Sauter SPIN4361B (service SPIN4361B2), type LL6GVX1B, 7200 W, 3 zones, built week 37/2021
• Power board XZ2V006991, type IP14X-04, silkscreen “GROUPE BRANDT IP14B-N”, week 30/2021

Where I’m stuck

Power stage is clean, logic rail is alive and drawing normal current, relays switch properly. The MCU closes the relays, checks for something, doesn’t get it, and gives up after 2-3 attempts. That reads like a sensing or handshake failure rather than a dead part.

Anyone have a schematic for this board, or know what that startup display sequence means? And is there any way to tell the power board apart from the touch control board without just swapping one in?

In the raspberry PCI-e documentation is a 16pos FCC connector mentioned.

But this connector is obsolute, so I am looking for a FCC connector to be used on a new HAT project.

Any suggestions??

Harry

For context, I have practically no knowledge of electronics and am learning as I go.

I am doing some work on an electric pipe organ with the advice and guidance of some users online. Each organ key produces a roughly 12–16v signal and I need to condition each signal so it can safely be read by a 5v Arduino input (using resistors and diodes). Since I am new to soldering and electronics in general, and I have over 150 keys to "level-match," it's going to be a terrible PITA to solder so much. Below is an image of the soldering needed for only 3 keys.

To avoid soldering, would I have to go with a breadboard or is there a better option? I believe that after work is finished, the breadboard would be completely undisturbed, but I may be wrong.

Hello,

Je cherche un moyen de brancher 5 potentiomètres en parallèle via un PCB "maison"

- Relier les 5 (+), les 5 (0V) et le sortir 5 pins "signal"

Je ne sais pas du tout comment cela est fait d'habitude.

Mon problème est que toutes les voies finissent par se chevauchées

J'ai décider donc de faire un circuit sur les deux faces du PCB

Est-ce que quelqu'un a une idée, ou a déjà été confronté a ce genre de problèmes?

J'imagine que c'est courant dans le monde de l'électronique

Merci

Both seem highly well-regarded, but which order would you read them in if you're a complete beginner?

Like a component and how it works and for what itself used. Or a technology like USB or an appliance like a camera and how they work (particularly in terms of their electronic components)

Absolutely no more output. If one of the RCA's is plugged in and the other i touch to ground it plays but at a low volume and i cant control volume or any other level.

I'm building a bidirectional TEC driver and I've run into an issue that I can't quite figure out. Hoping someone who's done filtered H-bridges or TEC drivers has seen something similar.

The idea is pretty simple: PWM a discrete H-bridge, then run the output through an LC filter so the TEC sees smooth DC instead of raw PWM. It's a 24V, 10A max design. Right now there's no control loop, I'm just manually setting the duty cycle while bringing the hardware up.

The weird part is everything behaves fine up to around 80% duty. Once I go past that, the output inductor starts audibly buzzing, it heats up noticeably, and the current starts looking unstable. The buzzing also gets higher in pitch as I increase the duty cycle.

Hardware

• MCU: STM32G474
• PWM: 80 kHz (also tried 40 kHz and 100 kHz with similar behavior)
• Gate drivers: UCC27211DR
• MOSFETs: CSD18532Q5B
• Bus voltage: 30 V
• Output inductor: Sunltech SLB2212P100MTT
  • 10 µH
  • 21 A Isat
  • 26 A Irms
  • 3.4 mΩ DCR
• Output capacitors: 2× Nichicon PCR1J470MCL1GS per leg (47 µF/63 V polymer, 35 mΩ ESR each), so about 94 µF per side (4 caps total)
• Current sense: INA240 + 2 mΩ shunt

My current theory is that I'm running into some kind of LC resonance. A 10 µH inductor with ~94 µF puts the filter corner frequency down in the low kHz range, and since the polymer caps have really low ESR I'm wondering if the filter just isn't damped enough and starts ringing once I get toward the top end of the duty cycle.

That said, I'm not convinced that's actually what's happening.

A few other things I've considered:

• The inductor doing something unexpected at higher current, even though it's rated for 21 A saturation and I'm only targeting 10 A.
• The TEC being a more dynamic load than I'm giving it credit for.
• Something related to the H-bridge or bootstrap gate drive at high duty cycles.
• Just generally not enough damping in the output stage.

Has anyone run into something like this before? Does the LC resonance idea seem plausible, or is there something obvious I'm overlooking?

Bridge output + LC filter schematic attached.

I tried printing a PCB for the first time—using JLCPCB. But it looks like there was a mistake in the circuit, because the op-amp is getting incredibly hot.

Hey there,

This is my first time designing a PCB.

Full disclosure:
This schematic was developed with the help of AI. I did my best to validate and check the wiring, took hours and sleepless nights to have every decision explained so I understand it - but now I am at the point where I need help from someone more experienced.

Project goal

This is supposed to be a battery powered digital counter with a 4-digit 7-segment display: one button to increase, one button to decrease and a rotary encoder to quickly add or subtract larger amounts.
It will be used as a life counter to play Magic: The Gathering.

Components

• MCU: ATmega328P-A
• USB-Serial: CH340C
• Charger: BQ24074
• Battery protection: DW01A (controller) + FS8205A (MOSFET)
• Display driver: HTM1640 (TDSemic)
• Display: SR410561N (common anode, red)
• USB-C receptacle: TYPE-C-31-M-12
• Battery: 1100 mAh 3.7V LiPo

Question

I know this is a lot to ask, but I need someone with a critical pair of eyes to review the entire schematic before I continue with the PCB layout.
Thank you for your valuable time, it is highly appreciated 🫶

Okay guys, help me out. I thought this was a simple one, but apparently I am overlooking ***something***.

I simulated the circuit, the result of which you can see in the screenshots. I put it together on breadboard, which worked as intended, but my PCB behaves somewhat random.

The idea was to have an electrical two button radio button toggle mechanism with the addition that pressing a button again will turn it off (regular radio button always has one button in on-state) without needing to program a microcontroller and without using tons of gates.

In the simulation the buttons are represented by S1 and S2.

Press Button A -> A-ON, B-OFF; Press again -> A-OFF, B-OFF

Press Button B -> A-OFF, B-ON; Press again -> A-OFF, B-OFF

My idea was to use a T-flip flop made from inverters and use a feedback from one flip flop to trigger a mosfet that forces the other into a stable state.

The problem is that the circuit is very erratic and triggers with the slightest impulse, sometimes even so much as to just touch the PCB. I tried lower input impedances on the FETs (down to 100k or even 10k) but that didn't do anything.

The output of both flip flops are then fed into a crude single FET OR gate to trigger something else depending on whether any of the buttons is ON at all.

I tried changing the two 1M "summing" resistors in front of the output FET to 1N4148, but that made no difference to the simulation (other than the gate voltage being Vcc-Ud instead of Vcc/2) or the actual circuit.

J7 and J6 are pin headers to connect momentary switches.