Why does the 2SD1426 (a 600 V, 3.5 A, NPN switching device) have an integrated 50 Ω resistor?

I would have thought that it would be cheaper (less silicon used) to use an external 50 Ω resistor.

Or, internally, is this transistor composed of an array of multiple (e.g. 10) small devices in parallel, each with a 500 Ω resistor?

If anyone can shed some light, please let me know, I'm intrigued!

https://www.alldatasheet.com/datasheet-pdf/view/2568/MOSPEC/2SD1426.html

Due to constant power outages because of destroyed grid i have to use charging station every day to keep using my pc. It has an UPS mode, meaning i plug it to power grid, and pc to the station, and i can use electricity directly from the grid while the station is charging. But here is where things getting weird.

My station has different charging speeds - 400, 800, 1200, 1800. The problem is that any mode except the 1800 and no charging causing vertical static line to appear on my monitor. They flicker fast and seem to be random. They are most noticable at 400 charging speed (that is the best since it does not overload the station, it does not even turns the coolers on at that speed), the sceen is covered with quite a lot of static in that mode. At 800 there are moderate amount, at 1200 - almost none, and at 1800 they disappear. They also do not appear if i do not charge the station.

Also sometimes when i turn charging to 400 spot my monitor turns off for a second.

Another weird thing is that when i attempted to record my screen to show how they look like - they disappear! But i managed to record it with phone: https://vimeo.com/manage/videos/1236197505

I am utterly confused. What it is? Why it only affects monitor and only at low charging speeds? Why it turns monitor off? Is it dangerous to hardware somehow? Someone please explain what is going on. And what should i do, always keep the max charge speed?

Hi I just got this cheap Old alarm clock radio I'd like to get working I have power to the clock and after opening the only thing wrong I can find seems to be this is something missing or am I missing something thank you

I just bought a batch of IRLZ44N N-channel MOSFET from robu.in and when testing if they were ok I discovered there was a dull metallic later on each and every one and I could scratch that off to reveal a shiny metallic later . Does this like stop the MOSFET from working as all test dead 🤔

Title. I've been working on some pet projects for a while now and I'm looking for diagram tools that I can use to map out my systems. I struggle to explain how my projects work when I'm showing them to people or asking for help, and I also want the documentation for my own use as I work with the components I'm "designing" (i use that term loosely as I'm pretty much re-inventing the wheel for my own educational benefit)

For some reference, I'm using a simulator to build a reduced-instruction 16-bit computer, mostly because I'm interested but also because I've been exploring computers for a long time and I wouldn't hate getting into the field professionally. Also, I know I need schooling to get into Comp Eng, but I'm just trying to get myself a baseline as the economy is kinda buns.

the beamz s700 smoke machine has a remote control with 2 leds and a push button. but the smoke machine has no dmx, so i cannot remotely make it produce smoke. i was thinking maybe it's possible to hack the remote control. i opened it up and measured that there is 220V AC between the brown and black wire. i thought maybe the best course of action is to have a custom pcb onto which i can solder the 3 wires and i can have remote control. so the pcb should have 2 leds and a processor and a component that electronically performs the job of the push button, so that via wifi i can remotely connect the 2 fields which previously were connected to the push button.

any advice on how to proceed? i don't know anything about making pcbs and there being AC involved feels kind of dangerous so this should be done with care and expertise.

I have this led panel as a backlight in a picture frame, but the usb-connector that powers it, was knocked off (see pic below). How can I resolder it back?

Canned air is getting expensive enough that I started looking at rechargeable dusters, but the ESD part is where I keep getting stuck. Some people say a short blast is fine as long as you hold the fan and don't scrape the board, while others make it sound like any dry plastic nozzle near exposed components is asking for trouble. For folks who work on electronics regularly, is the real concern the blower itself, the nozzle material, or just bad technique around unpowered boards?

I'm trying to read the EEPROM on this board.
Chip: Atmel 24C08N (I2C), right next to the NEC MCU.
Setup:
Black CH341A, SOIC8 clip with the green adapter
NeoProgrammer / AsProgrammer, _24C08 selected, I2C mode
Result: always "IC not responding".
I think the clip is powering the whole board and the voltage drops. I'd rather not desolder the chip or lift pin 8.
Is there any way to read it in-circuit, like powering the board separately or any help guys?

My low-side N-MOSFET turns on unintentionally when a 32V supply is applied to the drain. The gate has a series gate resistor, an external Miller capacitor (gate to drain), a Cgs capacitor and a gate-source pull-down resistor. I see a spike on the gate of the MOSFET, which turns on the transistor just enough to see a current spike through the drain.
I suspect dv/dt-induced turn-on through the Miller capacitance.
What should I check or change?

I live in an especially humid country and I recently bought an electronics component organizer (The 30 compartment Stanley organizer to be precise).

I previously used to keep my electronic components in a tightly sealed plastic box but the pins of most components eventually rusted due to high humidity.

This new component organizer is not sealed like my previous storage solution and I'm also planning to put 1 silica gel sachet in each compartment to help with the humidity.

Also, is it alright to not keep the mosfets, esp modules and other chips directly in the organizer without anti-static coverings?

Or should I use anti-static bags?

A while ago I bought a fluke ti32 wide1 lense but the seller did not include an SD card with required firmware to update the unit so it has the ability to do a wide fusion view.

Would someone here be able to provide me a digital copy of the contents of their sd card?

Here are original FLK-LENS/WIDE1 instructions:
https://media.fluke.com/b568f40d-2b11-41d3-8586-b10800c01515_original%20file.pdf

I contacted fluke customer support but they were unable to assist me:

Unfortunately, we no longer can supply the codes for your FLK-LENS/WIDE1. We no longer have the ablility.
...
I understand why you're asking. I have been with Fluke for over 25 years now. Not sure if that counts as an “old engineer”. That said I can tell you that the asset that was used to produce the information is no longer available to me or my team.

Does anyone have a fluke ti32 or know someone who does that also has either a tele1 or wide1 lense with firmware sd card?

Even if it was for the wrong model (TELE1) I could see the contents and format of the data is expected and try to reverse engineer it.

I tried ebay sellers and they all told me to kick rocks or sucker up and buy theirs (note most sellers don't even have it either or don't know it is required).

I am willing to pay a reward too.

I ordered some DDR4 green pcb DIMMs from Ebay and they came wrapped in aluminum foil. This seems weird. Is it?

I've noticed there are a lot of low cost (~$20) GPS tracking devices on Amazon, that have no monthly fee.

Does anyone know how they are able communicate their location back to the tracking device (phone)? I assume they must be using some cellular service, but there is no monthly fee. Is there some way they are able to send small amounts of data over cell networks for free?

It can't be Bluetooth, Wifi or UWB because the range is too short.

Apple Airtags use Bluetooth/UWB when the device is close by, but when it's out of range they connect to other random Apple devices in the area to send data.

But these aren't Apple devices, so how are they doing it?

Here are a couple of examples:

https://www.amazon.com/Real-Time-Location-Compatible-Wristband-Waterproof/dp/B0HJQLMWWS

https://www.amazon.com/Real-Time-Location-Wearable-Wristband-Waterproof/dp/B0HHJ2SYJF

It works but when you switch it off it either 1) stays on, 2) turns off, or 3) turns off and back on a few minutes later. Is this something that's somewhat easily fixable? Buying a new one will cost $100+

Idk whats next here with my school project, had claude help me but after putting the supply the relay isnt clicking, my supply is 9v battery but it says on the schematic source is 9-12v supply and the also the relay is 12v... so im thinking maybe the supply inst reaching the relay but my prof provided a supply for but somehow still didnt work

Despite it not being easy at all, taking a 12v dc source from a battery, how could I modulate it to 50 hz to then send it to the secondary winding of a transformer?

I'm trying to find a replacement for a right angle header connector that I got in a kit that I broke. I cannot figure out the mating vs. post length, and trying to do it by process of elimination on DigiKey is not helping. The picture is what they sent back when I asked, along with the description of "They are standard 90 degrees angled headers - both sides of the pins are of equal length." The pitch is 2.54mm. This is from a British group, if that makes a difference. Any help in identifying the contact and post length would be greatly appreciated.

Here is the link for the schematic circuit: https://www.falstad.com/s.php?s=QzJ7Ds

Instructions do not show the name of this component or how exactly to use to connect a power source

Have an OPA1656 (2 channel) wired up as an inverting amp with unity gain, off a tle2426 rail splitter to the +IN at 12Vdc. (only one channel shown in the image)
The Signal to the -In is, Input to board-> 2.2Uf Cap ->10kΩ resistor then branch to -In and also to another 10kΩ resistor (with a 22pF cap in parallel) to the output of the OpAmp. There is a 100nF cap from the V+ to Gnd. There is no oscillation.

Problem is, a 2Vpp 1khz signal before and after C10 is strong BUT there is only a 100-150Mv 1k signal on the output. Checked from pin 7 to gnd, and after C9 above...
The Audio input and OpAmp grounds share the same net, so nothing is floating.
Both the +In and -In are at the same voltage (hair less than 12) so the opamp IS managing that much. The other channel provides same exact nothing. none of the pins on the opamp or circuit that follows is shorted. R20 and R21 both measured to be 10k each. R22 and C10 both check out ok, no shorts....

I have been beating my self up for far too long. Does anyone have any ideas on why the opamp output is not giving me an inverted signal of the -In ???

I have an Ion Pathfinder 1st gen speaker with a brand new 12v 7.2Ah battery I put in, since the speaker sat in storage for over a year without getting charged and the original battery died. The speaker runs great with the new battery, but it refuses to charge when the speaker is plugged into AC power. I’m able to charge the 12v with a smart charger and it’ll hold the charge and run great, so the battery isn’t the issue. The speaker also runs with the 12v removed and the speaker plugged into AC power, and it reads over 15v on the output side of the internal power supply PCB. However, with the 12v disconnected it’s reading .11v on the terminals that connect to the 12v. With the 12v connected and probing “B+” labeled on the main PCB, its reading the same voltage as the 12v. Anyone have any ideas? It’s impossible to find replacement parts for this speaker and it was pretty expensive when I first bought it, so it’d be great to get it working normal again and not have to disassemble the entire thing every time I need to charge it. Thanks!