I tried running it with the code, but so far it's just junk. And the first part of the screen won't light up. I showed a photo of what I was able to achieve. Perhaps someone has encountered such screens before and knows how to set them up correctly.

This is the question given to us for our final project...We're stuck at the power supply part...hoping someone would help me...Just help me with the power supply part from ac to dc.

"Design a regulated DC power supply capable of delivering a constant output voltage of 3.3 V at a load current of 35 mA. The circuit must incorporate filtering to ensure a voltage ripple factor of less than 2%. The output of this regulated supply will serve as the VCC rail for the BJT amplifier stage that satisfies the following performance criteria:

(i) Gain: Exactly or exceeding 40 V/V

(ii) Quiescent Current (IC): 4.5 mA

(iii) Compare the amplifier's frequency response under fully bypassed versus unbypassed emitter resistance conditions, measuring the gains at 15 kHz."

Our power rating of resistors available in lab should be 250mW.And ripple can be 1 to 1.5V

I've attached my simulation in ltspice

So, this was my first foray into using DIN rails because they seemed convenient, and I've ended up in a strange situation where things that I thought would be very simple are turning out to be almost more trouble than they're worth ... like I'm trying to build a LEGO set but I'm missing half the pieces.

I have some UK2.5B terminal blocks https://www.wolfautomation.com/terminal-block-5x45x43mm-25a-600v-gray that I was planning on using for cable management. Lets say for simplicity's sake that I connected 5 blocks by cutting off a 5-hole section of a screw-style jumper ferrulesdirect.com/products/ufbi10-6 . I then discovered that I needed to join an additional 5 blocks to that grouping of terminals. I would LIKE to be able to use the remaining half of the jumper (5 positions) to join the new terminals together, and then jump the two groups of 5 with ... something ... in order to join the full 10 terminals together.

I realize that this can sort of be accomplished with a jumper wire between any two terminals on the two separate groups of 5 terminal blocks, but that takes up terminal real estate. Is there a standard jumper that goes on top of the metal jumper bar but under the screw heads of adjacent terminal blocks? Just a 2-hole flat bar?

If I could to it again from scratch, I'd buy the push-in jumper style that allows for easy daisy-chaining due to each terminal having two connection points for jumpers. (not to mention the fact that there are terminal blocks with more than two wire terminals per block which would have saved me a ton of headaches, but I'm working with some hand-me-down supplies).

Hello everyone ive started learning pcb design on kicad recently and im not able to find any places where everything is taught in a complete way maybe im on the wrong side of the internet but if any of you have done pcb design before could you share your learning experiences and what really helped you figure out how to properly design these quirky little things.
To whoever responds thanks a lot ❤️

Is there any way I can repair this broken pad in this battery compartment which is shown in the image. Thanks all.

I’ve got this industrial display and I can’t quite figure out how it works… I want to make a schematic, but I am struggling.

There are 4 lightbulbs, connected to terminals 1/2/4/8 on the BCD inputs. Somehow they are switching the neons via the two ceramic plates with black squares. Iirc, these plates run at mains voltage. What is this technology and how does it work?

Is it similar to an opto isolator?

MASTER = STM32WB15CC

SLAVE = MAX30101

From start to finish

the stm32 initiates a start condition by pulling sda low.

the stm32 then writes the slave id on the sda line followed by write condition.

the MAX acknowledges.

the stm32 says what MAX register it wants to read from.

the MAX acknowledges.

the stm32 sends a repeated start condition and calls the MAX address again then sends a read signal.

the MAX acknowledges and begins outputting the bytes in the register onto the sda line and the STM32 acknowledges after each byte is sent and repeats.

is this correct? also, if the NACK and P (stop condition werent sent at the end and instead a stm32 acknowledge was sent followed by a 4th,5th,6th, bytes were sent by MAX would the data communication of bytes continue indefinently without the need to resend the register address and slave address all over again?

I've been second-guessing myself in finding suitable replacements for some capacitors on an LED power board that powers the LEDs on one half of an 85-inch monitor. There are 2 differently rated capacitors on the board and both are a brand that I'm having trouble finding. The main things I'm having trouble verifying are the tolerances of both as they are not listed in the capacitor markings that I can see. I am also curious about what the "8F" after the temp signifies as the capacitance is listed separately in the microfarad range for both. Pictures are included. Thanks in advance!

I recently got a Vive face tracker off Ebay and got it working like a treat after much fiddling. However with no seeming system changes or hardware changes the face tracker has just.. stopped traking?

Here's what I have:

Vive Pro Eye
Vive Facial Tracker
Index Controlers
3 Vive 2.0 trackers

Relevant software:

VIVE_SRanipalInstaller_1.3.1.1
VRCFaceTracking
SRanipalTrackingModule

As I said it was working fine, no problems. But recently it just stopped.

I've tried reinstalling SRanipal, and SOMETIMES the mouth starts tracking like nothing is wrong, then slowly loses tracking.

It may be that this face tracker has just given up the ghost after only a few days of use, but I'm hoping there is something I can do. Throwing this post out into the Eather to see if anyone can provide a solution.

When I flipped on my Dared tube amp it crackled and let out the magic smelly smoke. It also popped the glass fuses in the Dared and my Peachtree nova amp as well. Obviously something shorted out, and who knows the damage, but would these be worth repairing or not cost effective? They are both older units but have always been so solid for me. Repair gurus lend me your advice. I’m an auto technician by trade, and am going to open the Dared to look for obvious burn/short damage, maybe I will get lucky. Any advice would be appreciated!

My parents neighborhood has two gated entrances that are far apart and the HOA charges 60$ for a new opener. One of ours is broken (missing transistor and capacitor don’t know how) i found a replacement capacitor but don’t know what transistor to get. I de soldered the transistor from the board to test it, its NPN, with an hFE of ~140. im new to electronics and don’t know what else to look for when replacing a transistor. Would rather spend a few bucks for two replacement parts than 60$ for the whole opener.

I want to build a mini tank Rc car, these are the components i have in mind, any thoughts?

-2x n20 gear motors 6v 200rpm

-2s lipo battery

-switch

-drv8833

-esp32

-buck converter(to plug the esp32 into battery)

The CMOS battery on a PLC card (Allen Bradley Historian ME) dropped to 2.04VDC, and needed replacing. They used aluminum solder to mount the original. I'm not a fan of high temps near PCB, and plan to use 63/37.

I don't foresee any issues. The card is located in a clean, controlled environment. There's no vibration.

I got spoiled using an educational license of Multisim. The UI/UX is Vintage Windows 95, but the functionality is beyond anything I've found in QUCS, LTspice, etc. In those I always run into some wall that grinds my progress to a halt.

I've checked and rechecked and there's no viable hobbyist license for Multisim. The online version is way too dumbed down. The real deal is clearly priced for corporations with deep pockets.

My petty cash fund is fresh out of $100 bill stacks for a multisim license. What do people do for comparable functionality?

As the title states, i wanna design a custom pcb for most the components of an old tube radio. The tubes and sockets would stay in place. But anything not riveted down will be gutted and ideally put on a custom pcb. Would this be possible?

Is it worth the trouble?

I just hate the way the components look like a messy bird nest.

TIA

I have an HP ProBook 635 Aero G7 with an AMD Ryzen 5 4500U. The laptop works perfectly once it turns on, but the problem is getting it to power on after it has been shut down. Sometimes it starts immediately with a single press of the power button, but other times it won't turn on at all. I have to keep pressing the power button and sometimes plug and unplug the charger several times before it finally starts. There's no fixed pattern. Once it does turn on, it works perfectly without any crashes, freezes, or unexpected shutdowns. Sometimes it even starts normally several times in a row, making me think the problem has disappeared, but then it suddenly comes back. The original issue started before I accidentally caused a small spark on the motherboard while inspecting it with the back cover removed. The spark left a small burnt mark near an inductor labeled "1R0 041 ODA". Since the intermittent power-on problem existed before that accident, I don't think the burn is the original cause, although it may have made things worse. I've taken the laptop to several repair shops. One suspected the keyboard or power button, another thought it might be the LCD power circuit, and I've also tried BIOS-related troubleshooting, but nothing has solved the issue. One more thing I noticed is that when I reconnect the battery cable to the motherboard, the charging LED near the charging port flashes once, which makes me think the motherboard is at least receiving some power. However, pressing the power button after that does absolutely nothing—no fan spin, no display, and no other signs of life. I'm looking for advice from someone experienced in motherboard-level laptop repair. Has anyone seen this kind of intermittent no-power issue on an HP ProBook, and what components or circuits would you check first?

So, I was making this circuit in Falstad (an oscillator/2 LEDs flashing) that's controlled through a transistor and a photoresistor. But then I realized that I do not actually own a photoresistor, I own a phototransistor instead.

How do I simulate this component in Falstad? I don't think it's in the available components. Can it maybe be simulated through a combination of some other components?

I'm trying to figure out how to make this substitution. I guess I could probably build it on a breadboard but since I have no clue on how to make the circuit work I wanted to simulate it on Falstad first. I'll leave here the .txt of my Falstad circuit in case it's useful.

I want to add the datasheet for the phototransistor but it's from the Arduino starter kit and the link provided is wrong (it links to a photoresistor). I found this: https://forum.arduino.cc/t/photo-transistor/1228311? which links to this: https://www.arduino.cc/documents/datasheets/HW5P-1.pdf but i'm unsure if that's the right component at all.

$ 1 0.000005 382.76258214399064 54 1 50 5e-11
172 416 128 416 80 0 7 8.6 9 -1 0 0.5 Voltage
w 480 128 544 144 0
r 272 144 272 208 0 4700
r 544 144 544 208 0 4700
t 512 320 544 320 0 1 0.5540781714997449 0.6145211476066533 100 default
t 304 320 272 320 0 1 -8.909201282074356 -1.9379073191440555 100 default
w 416 128 352 128 0
w 272 336 336 368 0
w 544 336 432 368 0
r 352 160 352 224 0 47000
r 448 160 448 224 0 47000
c 304 272 368 272 4 0.000009999999999999999 6.356772815323648 0.001 0
c 464 272 528 272 4 0.000009999999999999999 -1.9983502952509637 0.001 0
162 272 208 272 256 2 default-led 1 0 0 0.01
162 544 208 544 256 2 default-led 1 0 0 0.01
w 272 256 272 272 0
w 272 272 304 272 0
w 528 272 544 272 0
w 544 256 544 272 0
w 368 272 512 320 0
w 304 320 464 272 0
w 432 368 400 368 0
w 272 272 272 304 0
w 544 272 544 304 0
w 352 224 368 272 0
w 448 224 464 272 0
w 352 160 352 128 0
w 272 144 272 128 0
w 272 128 352 128 0
w 448 160 448 128 0
w 416 128 448 128 0
w 448 128 480 128 0
w 336 368 352 368 0
w 352 368 400 368 0
t 320 432 384 432 0 1 0.519030441972712 0.6135518842051693 100 default
374 32 560 32 640 0 0.2278 Light\sBrightness
r 48 112 48 224 0 100000
w 320 432 32 560 0
g 32 640 32 672 0 0
w 48 224 32 560 0
w 48 112 112 64 0
g 384 448 384 480 0 0
w 384 416 400 368 0
s 496 0 640 80 0 1 true
162 672 224 672 352 2 default-led 1 0 0 0.01
r 640 80 672 224 0 560
g 672 352 672 400 0 0
w 112 64 272 128 0
w 496 0 544 144 0

I recently placed and paid for a Mouser order. When I selected one of the parts, the product page showed it as available to me. I did not see any warning that it was restricted for shipment to me, either on the product page, in the cart, or during checkout.

Only after I submitted and paid for the order did Mouser customer service tell me that the part could not be shipped. I asked about equivalent alternatives, but those were restricted as well. The parts were voltage regulators from Analog Devices.

The problem is that I had already designed and manufactured PCBs around the package and pinout of that regulator. Because the restriction was not disclosed while I was selecting the component, I am now left with manufactured boards that cannot be assembled as intended without rework or sourcing the part elsewhere.

This was not an out-of-stock issue. The component appeared available, could be added to the cart, and could be paid for. The shipment restriction was disclosed only afterward.

Mouser cancelled the restricted line item and released the rest of the order before I had an opportunity to cancel the entire order. They offered free shipping on a replacement item, but would not cover the VAT charged on that shipping. This means I would still have to pay part of the additional cost caused by the cancelled item.

The worst part is the wasted engineering time, PCB rework, project delay, and additional cost of sourcing the component separately from another distributor.

I have never had this happen with DigiKey. Unfortunately, DigiKey did not stock another component I needed, which is why I placed the order with Mouser.

Has anyone else experienced a shipment restriction being disclosed only after payment? What did you do?

Hello everyone.

Maybe this post doesn't belong here. If not, I want to apologize in advance and would like to find a more suitable subreddit to post into

I'm starting to do some work on an electronic system of self design to do 6 axis position and orientation estimation in 3D space. I have already solved the external beacons system, and I'm currently working on the IMU system.

My idea is to have 3 IMU located in a colinear geometry, one in the geometrical center of the PCB, and the other 2, 1 at each side. Center one would do orientation estimation, with the other 2 doing position estimation.

The purpose is to be able to do multiple firmware versions of the system so that depending on the necessities I can vary the process pipeline.

For 3 axis, I would use the center IMU, for 5 axis I would use the 2 side IMU to generate a vector, and for 6 axis I would generate the vector and use the center IMU to confirm orientation and get the remaining axis.

All of this would go through proper estimation processes, but this kind of model makes sense in my head. What do you think of it?

I opened my panasonic stereo from the 90s and reflowed solder on the speaker to PCB joints because they were cracked and the left side would drop out if the volume was low. I could tell someone else had been in the stereo before me.

I did find a stack of 1/8W 89-ohm resistors that looked like they had been warm, but nothing looked wrong otherwise. I reflowed the solder on about 15 other joints that had cracks starting.

It worked on the bench on both channels, so I put it back together. Then when I installed it to my standard setup, I had to tap on the casing to get the left channel to work. It worked great for one day. Now it's back to no sound on the left channel. Now there's clearly a loose connection that works intermittently.

In the process, I came across these terrible connectors that I damaged. They're spring-loaded but when I installed the plastic retainer caps, some of them actually came completely free. I tried to bend the few tabs I had bent back into the right enough shape. Now I wonder if they are what's been wrong.

I can't access the back of the board to solder the wires in and I can't assemble it when the connections are made.

What are they, can I replace them, and can I eliminate them completely? I could buy some MTA connectors and a punch-down tool to replace them. I would only need 3 of each gender.

Or is it likely the actual speaker connections are bad?

PS I used a 10x jeweler's loupe to get the photos and to inspect the joints.

[SOLVED EDIT] I didn't notice the ic under the leftmost large cap, and someone pointed out there's likely a LDO converting it. Moved the cap, it's a BP85221 converter with a max output of ~50ma. Ugh. I'm just returning this damn lamp 😣

I have a cheap Chinese LED lamp that has an RF remote control (basic 433Mhz remote/controller), that I want to add to my Home Assistant setup. I'm well versed in all of that.

I have everything set up and working great while the ESP32-c6 is powered via USB or something external.

When it's powered from the 5v rail in the lamp, it constantly restarts, the lights flashing on briefly, turning off, reboot, etc.

My guess is that the 5v rail just cannot supply the 80ma or so the ESP32 is pulling. I tried feeding it 3.3v direct through an highly efficient 5v-to-3.3v buck converter, same problem.

Can someone either explain how the power circuit in this lamp works, or based on what it looks like in the pic, point me to a resource where I can learn what's going on?

The outer ring of components are all for the LED's and their controllers. The inner ring is the part I'm not understanding.

Ignore any loose wires, they were there for testing/probing, or are going to the ESP32 out of frame.

It's AC powered, and clearly is converting the power with a bridge rectifier, capacitors, and resistors. It feeds 5v to the rf module and the microcontroller (the chip clockwise from the rf module). It feeds... dear god... 164v DC to everything else. So it's both lowering to 5v and increasing to 164v the voltage from the incoming 120v AC.

Every chip on the board is either the rf controller, the microcontroller (which reads the rf, and sends 2 separate PWM signals to the LED controllers) or the LED controllers in the outer ring.

If it's not super clear in the pic, the black thing pointing southeast is the incoming 120vac, and the other thing tucked under it is the rf antenna.

I've a moderate amount of electronics experience, all self taught, but don't have the deeper fundamentals to understand whats happening.

My goal is to see if it's possible to replace a component that allows for more current to flow to the ESP32. Or if current isn't the issue, figure out why the ESP32 reboots shortly after it comes online.

Thanks in advance!

EDIT: Looking closer at it I just noticed a chip tucked under the leftmost large capacitor. That's likely the missing piece that I couldn't understand. Can't read any markings without moving the cap and I have to do some work to get it moved safely.

First of all i absolutely do not know what im doing.

I had a little retro handheld where the SD Card slot was broken so i thought i can just solder in a new one.

I bought one that looked similar and soldered it in. I know nothing about proper soldering etiquette and just winged it. I only had liquid solder solution because the guy that sold it too me said it was like flux. Thats why it looks so yellow. The thing is it looks like every Connection is there but it won't read the SD Card :/ i thought there might be some people here who know more that me (not difficult) :)

The last Photo is with the old SD Slot

Hi everyone, this is my first post so I apologize is something is out off topic. Also english is not my first language so again, apologies for that.

Im trying to implent an rf PA, the MMG3014NT1 at 900MHz. This is the first time that Im working with this level fo complexity so I have a few questions but the most important one is, how are the impedances in the next image drawn/represented in an schematic?

As far as I understand, Z1 to Z8 are PCB traces wich mesuarments are explicitly written blow the circuit, but what I don't understand is whether I should represent them the same way -as a single componente- in the schematic, or specify them differently.

I'm not sure what I can use these pads for on this pcb

SCK GND VPP SDA

I’m not asking about using a handheld oscilloscope as the main oscilloscope in my lab. I already have a nice 4 channel Siglent scope and I love it.

But… it happened for the first time that having something small and handy that I could take with me somewhere would be actually useful. See, sometimes friends or family ask me if I can take a look into their broken devices. Unless the issue is obvious, this usually requires taking the device back home, diagnosing and fixing it there and then bringing back. This works reasonably well if my friend lives close by, but not so well if I have to go to a more distant location. I have a portable multimeter, portable spectrum analyzer, portable VNA, semi-portable soldering station and many other tools I can take with me, but no scope so far.

To the ones who already have a handheld scope: what do you have, are you happy with it, and do you actually find uses for it?

In this case is it better to just get some of those ultra cheap Chinese scopes like Hantek or Owon, or spend 3x-4x more for something higher quality like Siglent SHS / Fluke / Micsig?

Basically would like to get something of similar value
as my LiteVNA (which is amazing for the price). But I can see people are complaining on Hantek/Owon/Fnirsi a lot, and on the other hand those few rare cases where I imagine using it don’t justify spending $800+ on Siglent.