Ask Electronics

I have a simple circuit where 5V signal is fed into a buffer (Nexperia 74LVC1G07), then from the buffer into another device. The buffer is fed 5V by a switching DC-DC (R-78HB5.0-0.5/W). After it's been off for a while, the buffer works, the signal is recognized by the receiver. This continues for some time, minutes, to tens of minutes. Then the buffer stops working. The DC-DC still works as well as the source. If I unplug it and let it sit for an hour, it resets back to working for a while until it stops.

Context:

The setup runs on an ebike 36V battery. Theres a hub motor connected to the same battery (via power controller). The signal source is a torque sensor. The destination is a bike computer.

Any idea what could be causing this? I don't know much about electronics. I learn specific bits to do something but I'm ignorant otherwise. E.g. I know what a buffer does, I understand how it works on high level but I have no clue for example how it could be affected by the rest of the system electrically through noise, EMI, etc. My physics intuition here makes me think there must be some charge buildup happening which dissipates with time when turned off. I've no idea if this is remotely valid, or if it is how to fix it. Any ideas are appreciated!

I just found out I can buy a decent 400W solar panel in the local hardware store for around 90€ these days.

Are there people around with experience in off-grid solar? There is quite some supply in cheap MPTT charge controllers on the internet. And I can't afford a 700€ power station. But I would be able to buy a few power tool batteries or one of the lead-acid batteries people put in their caravan. Are there projects building a power station myself? Is this even worth it?

Maybe someone alredy wrote a blog post with recommendations or findings and failures along the way. Or has something similar running at home?

(Thanks to the mods for steering me towards the correct community.)

Hi all. Does anyone have experience with the BMSs from Daly? I'm looking to get a 16s BMS for a DIY li ion battery pack. I have a large box full of li ion 18650 cells and want to make an emergency battery system for home use.

That power outage in Spain motivated me to finish this project.

I'm using an Arduino and through a library working with an IC (MCP2515, a CAN controller) over SPI. The IC indicates interrupts by causing a falling edge on an interrupt pin.

Components are connected using jumper wires on a breadboard.

• When a logic analyzer is not attached, the IRQ gets called a few hundred times. It should only be called once. I thought it must be noise on the external interrupt pin but a pull-up doesn't help. I've tried the internal pullup and an external one.
• Trying to see if there is a ton of interrupts from the IC, or an error internal to the Arduino, I attach my logic analyzer. Now it works perfect.

Any idea what might cause such a weird issue? Looking around I haven't found anything.

EDIT: I found a Reddit post for a different circuit where a user suggested placing a small capacitor to make the edges of a signal rise slower. This has fixed my problem.

Since I've already created a post: does anyone know why I was getting an unending number of interrupts? Why would the edges of the interrupt signal changing too fast cause something like this?

It's the trace going towards the mode button, so I'm pretty sure resistance won't exactly be critical over a ~3mm gap, as long as it recognizes when the plunger button is pressed down.

Not sure if this is a dumb question but this has me quite puzzled.

The legs on TO220 packages are very small. How is it that there are e.g MOSFETS rated as being able to continuously conduct ~100A? e.g IRF1404Z

From what I understand such large currents need busbars on PCBs and these appear a lot larger than the legs on these components.

I have an inspection scope camera that I'm attempting to repair. It's one with a camera on the end of a flexible rod to see into tight spaces. The pins that lead to the camera came out of the connector. I tried looking for teardowns or even replacement parts, but found nothing.

Two pins are still inserted, but I'm not confident they are in the right places. I want to get it working without the risk of frying everything. I've done my best to find where each pin goes, but there's not enough info for me figure it out on my own. The camera rod also includes an LED for light.

Here's a photo of the connector as it is:

And here is the socket with it's pins labeled (the labels correspond to the testing pads and not to the socket pins):

Here's a zoomed out pic if it's of any use:

I have a multimeter, so I can do any testing you can suggest. Unfortunately, I was not able to disassemble the camera to trace any wires.

I replaced this battery last fall, but it has drained over the winter. The auto-mower dock wont charge it. Is there any feasible way to charge it safely? Or is it dead at that voltage? It’s a Bosch Indego 400. Thanks in advance.

Hi, Any1 have experience with this usb to TTL 6 pin converters? I just want to know if I have a dodgy one that I bought from Ali or normal behaviour.

Doesnt seem right. I have it plugged to a powerbank, following voltages read from pinout, without any jumper link.

5v = 5.3 Vcc = 3.9v 3.3 = 3.2v Tx RX = 3.9v

If I use jumper link from 5v to VCC, then tx RX = 5.3v, if I jumper link VCC and 3.3, RX and tx = 3.9v.

Thanks for reading

Photo of product http://0x0.st/81fc.jpg

I'm making a driver for a small 15V, hall sensored, 9-slot BLDC motor I got off of AliExpress. It has u,v,w inputs. Three hall outputs and Vcc, Gnd for them. No datasheet :)

I understand the working principle: I'll have to use the hall sensors to figure out the location of the rotor, then power the appropriate windings.

Trouble is, I don't know how the windings for the three phases are arranged within the motor. So I don't know which pin to give power to, because I don't know which windings within the motor will then be powered.

How can I figure out where the windings are for each phase?

I'm guessing I've got to manually spin the motor and do some detective work with back-emf measurements and hall sensor outputs to figure this out?

So I'm not sure what the right community for this is but I'm hoping yall can help. I'm a refrigeration service tech and recently I was tasked with replacing a sensor in a room used to store ethanol drums. Due to the nature of the room every device in it had to be rated explosion proof and I couldn't use any tools that could pose any risk of ignition (no heat gun, basically nothing with an electric motor, and definitely no open flames) while working in there. Normally when I splice wires I use heatshrink to cover the splice simply because it looks far more professional than electrical tape and it holds up better over time. However in this case I could not figure out any way of shrinking said heatshrink without posing a potential ignition hazard so I was stuck just wrapping the splice in tape. We do a lot of work for this company so I'm hoping to find a better solution for the next time I am in a similar situation.

So do any of you know any way to shrink heatshrink without posing an ignition hazard or am I stuck just using tape in those situations?

I'd like to build a small light that i can use to cast a shadow to a wall.

It needs a single led that's really small and bright and that can be recharged. Also I want to put it in a special casing.

However I don't really know how to build one myself. So I had the I bright idea to take apart a flashlight that is rechargeable, but I'm not sure which one can be dismantled.

Do you have any idea what flashlight I could use or what parts I would need?

Why do you like it? Why did you choose it? Would you recommend it?

I'm looking for a recommendation on a high quality 2 or 3 meter USB-C /Thunderbolt cable used for data transfer and charging.

After yet another replacement Anker cable usb-c cable I’d really like to get cables that can last a few hundred cycles and I need a recommendation.

Are there any companies that make higher durability cables?

--Edit-- So far recommendations I have gotten are

• Samsung
• LCom
• cable matters
• Braided jackets
• Power delivery of 25w or greater
• Use magnetic disconnects

So, i'm thinking of a story and i need some tech info.

How risky is to de-solder an usb plug if the flash-drive contains important files? It would be relatively safe for someone capable, or the heat is way too risky for the chip/content?

Also there's any (MacGyver like) way to quickly access the file or reconnect the plug without a solder while only having access to office supplies?

I have a pet project I've been working on to modernize an electric organ console, and one of the final things needed are toggle switches. On a modern organ these are able to be manually toggled, or they can be flipped up/down programmatically using electromagnets (video). The ones purpose built for this are obscenely expensive but I can't find anything even remotely similar. Am I crazy for thinking this kind of switch are used in more things than just organs?

Hi all,

Do you have some recommendations for a soldering station that would meet my needs?

I've been into hobby electronics for a few years, doing mostly analog audio projects but recently got into repairing and repurposing broken electronics (Bluetooth earbuds, speakers, USB cables and such).

I've been using a cheap Parkside(LIDL)-rebranded "generic Chinese product" (I came across the exact same model on AliExpress, in different colors); which has served me well until now but has a few flaws that I can't be bothered with anymore. Mainly: -it takes ages to get hot. -the cable going from the station to the iron is super thick and stiff, which is annoying as hell...

I would like it to be the least expensive possible, while being good enough I'd be happy with it for the foreseeable future.

I have been looking at these:

Old tech, cheap tips (<1€)

Newer tech, "expensive" tips (8-10€)

And wondering how these "newer" types of iron compare to stations, what are the main drawbacks?

Thanks a lot in advance for any input, Please be gentle if you think I'm an idiot :)

Edit: changed the "Smolderin" in title to "soldering"

I haven't really been able to find much on this. I recognize the totem-pole and what that's for. Would love help understanding:

• What's the triangle?
• What's the rectangle immediately after?
• Why are there two outputs instead of one? A lecture I watched claimed this is common.

I've got a few projects on the list which will be battery powered. I'm thinking of using 18650s just because of how ubiquitous they are, but I know there's other options out there. Are they worth it?

• E-ink calendar
• Solder fume extractor
• Lora station
• Portable "trail camera"
• Home assistant remote controls Etc etc etc

So, I had some issues with installing the GPU in the case, and the GPU bottom (those metals things at the bottom) ended up scratching part of the motherboard. From what I can tell, there's a bunch of similar components all the way up, so I'd think there's redundancy, so I guess it's not that important. Here is a picture (I was told some people couldn't open postimg, both links have same image):

https://i.postimg.cc/7LBwkr3h/62e626.jpg

https://files.catbox.moe/62e626.jpg

PC boots fine into bios, fans work, stuff are recognized, mouse and keyboard also works, but I haven't really done much beyond that.

Motherboard is: MSI B650 Gaming Plus Wifi

It's located here, and on them, it is written K72 then vertically smaller K2 (the 2 has an underline), as you can see in the above image too:

https://i.postimg.cc/XJNcnppT/modelblock-gaming-pd.png

https://files.catbox.moe/7otcn6.png

I was told to ask here, and the best guess from what I've been told is that this is this:

Paralleling power metal-oxide semiconductor field-effect transistors (MOSFETs) is a common wayto reduce conduction losses and spread power dissipation over multiple devices to limit the maximum junction temperature.

Which could mean that the others could pick up the slack.

Should I get a new motherboard?

It's not available anymore and even if it was, I don't really want to buy one from him. And I need about 15 anyway for the youth group activity. It's far more cost effective to order direct from pcb fab shop.

I’m working on driving a very finicky lcd. I have it working now with an FPGA dev kit. I had to use an FPGA because some of the timing requirements are in the tens of nanoseconds.

At the end of the day, I wrote a block for a one shot/continuous clock with a programmable duty cycle and initial delay. This block was repeated six times for the various clocks with their specific values.

Moving to the final product, this feels like overkill. In the past, I’ve managed to make this kind of thing work with a Rube Goldberg collection of on-board timer/counters on the microcontroller.

I’d like to avoid that mess this time around. If I can generate the clocks externally, I can have the host MCU send the data quickly using DMA.

An FPGA works great, but they’re expensive and there’s the issue of licensing for FPGA and and CPLD software.

I’ve seen this problem solved with a lookup table, but there aren’t a lot of cheap/small rom/ram options for what I’m trying to do.

Basically, what I’m asking is is there a component that can be easily programmed to generate a number of clocks, doesn’t need any costly software licensing, and comes in a very small package? (Like wlcsp)

Found metal weight inside

I wanted to learn more about electronics, and I found this https://www.open.edu/openlearn/science-maths-technology/an-introduction-electronics/content-section-0 to start from so I can have a grasp on theories first, and I want to try learning microcontrollers afterwards but I can't afford to buy any IRL atm, are there any softwares to simulate them to assist on learning without having the physical hardware? I'd be happy if anyone could give me any tips toward that, thank you if you read this far