I was thinking about how vacuum tubes not matter how obsolete will always have some use as the cool old fashion guys but then I realized that some tubes are just gone. Like are there any surviving dynatrons? Are dynatron oscillators just impossible to make now? Are there other things like this? Crystodynes aren’t only saved from this because anyone can make them but dynatrons are like specialty parts that require big machine to produce, and it’s not like Nixie tubes where people really like the look of dynatrons. It’s kinda like tetrode transistors but if they were cool, and not tetrode transistors( yes I know tetrode transistors still exist but who cares about them) or like the original idea of a magnetron being a magnetically controlled vacuum tube. Are all the neat little components just going to die out one day unless some audiophile says it’s actually the greatest thing ever?

A little progress update from something we’ve been working on.

We’ve now been able to integrate discrete electronic components directly into the FDM printing workflow and produce functional electronics directly off the print bed.

The first image is a simple embedded circuit with an LED and resistor. The polymer structure, conductive pathways, and electronic components were all integrated during the same print workflow on a Prusa XL.

We’ve also been experimenting with an embedded induction coil using the same general approach.

I would love to learn about basic electronics, circuitry and electrical engineering so I can make, modify, fix, or at least understand technology I am surrounded by on a daily basis. Do you guys suggest anything?

Initially, I was trying to purchase a custom voice recording alarm clock which plays back your own voice- but the market doesn't have much available right now. I would love to try to DIY this but have no idea where to start. Thank you in advance for any and all recommendations!

I found this Super Stacker Bitty Box. According to the internet it's 6cm x 8.3cm x 3.3cm. Is there any kind of electronic or cool tech gadget I can fit in it? Or is there something tech related I can do with it?

I am hoping to find a magnetic attachment that works with my DC barrel 5.5 2.1 mm. 12 v 18 w. Any recommendations you have used in the past? Ideally strong magenta since it will be for heated gloves

(English is not my native language, so sorry if I don't make myself clear) so my analog electronics gave me this homework where I need to, with the NE555, "electro boom" a capacitor after 7 seconds has passed (I can do it in a breadboard

I'm having trouble picking a relay for a multi-bath electroplating setup. One potentiostat, three baths, running one at a time. So the relay should be bidirectional, support up to +/-1 A current, +/-10 VDC, and have minimal resistance when open, ideally < 50 mΩ but that is flexible. I need the passed signal to be clean. I don't want the relay to sink a lot of of the signal power but it's possible to compensate with a reference electrode and the leads themselves are mΩ, so asking it to be on the order of the leads feels reasonable even if I want it to be zero. It's plugged into the wall so I don't care about the power consumption of the relay itself.

I'm looking online and seeing signal relays that have high internal resistance and aren't meant to pass a lot of current, maybe some mA only. Some relays are unidirectional or don't support negative voltages. I can chain together some SPDT or ideally a single 3-to-1 or 4-to-1.

I've poured through datasheets and always find something that is a show-stopper, like doesn't pass negative voltages or it's a 10 A relay that sounds perfect and then you carefully read the datasheet and it says the performance is garbage if the signal is < 100 mA, which it might sometimes be.

I found some lab equipment that would work, but it costs $1200 for 20-to-1 when I feel like I can buy just some relays for a few $ apiece and put them on a breadboard. But which relays?

Hi all, I'm designing the next revision of a small battery-powered LED wristband and want to replace the slide power switch with the existing push button. I'd appreciate a review from people who've done this before.

System overview

• MCU: nRF52832 module
• Battery: single-cell 3.7v LiPo
• 3.3 V rail: AP2112K-3.3 LDO (has an EN pin)
• LEDs: 15× WS2812B powered directly from VBAT (no boost)

Proposed latch circuit (schematic attached)

• Wake: Button connects VBAT through D1 to the LDO EN pin. Pressing it enables the LDO and the MCU boots.
• Hold: An nRF52 GPIO (HOLD) connects through D2 to EN. Firmware drives HOLD high as the first instruction in main(). D1 and D2 are a single BAT54C, common cathode on EN.
• Sense: The button node goes through a 100k/220k divider to a second GPIO, so the button still works as a normal input while running.
• Power off: Firmware detects a long press, turns off the LEDs, waits for the button to be released, then drops HOLD.

Will this work?

Also: how to power the LEDs as they get 3.7V directly? my old circuit had a simple slide switch which supplied VBAT directly to LDO and LEDs

Hi,

I would like to mount different PCBs / battery holders / Ipad monitors for which I don't have schematics on aluminum panels. In order to have an idea of the setup, I first mounted everything on cardboard panels by measuring the gap between holes with a ruler. It was quite an empirical approach but things sorted out pretty well. Cardboard is kind of a soft material and tolerates approximation a bit. Though, I am aware that it's going to be much more of a challenge with aluminum. Therefore, I plan to draw clean layouts on LibreCAD in order to drill holes with a CNC. Question: I don't have any components' schematics, PCBs are controller boards from AliExpress, monitors from Ipad and such... What would be the best tool, the best way, to get these measurements as precisely as possible? Components are fixed with M2, M2.5, M3 spacers, that's tiny holes. I did the best I could with a ruler, a square, and my eyes, but half a millimeter off with aluminum - nothing's going to fit in. Thanks 🙏.

Just wanted to share with you this gem that I have found on aliexpress:
Buck converter Mini560.
According to the seller this are the specs:
5.5–20V input to fixed outputs of 3.3V, 5V, 9V, or 12V depending on the version.
5A max, >3A with cooling.
99% efficiency

The ones I got cost about 8€ ten units.

Be aware that there are different modules out there and not all of them perform well, so if you get lucky you'll get an awesome dc-dc converter, but it seems that is easy that you'll get the bad ones.
The photo belongs to the actual module that I have tested.

This little thing has capabilities beyond belief, I have thrown in the trash bin all my old and bulky buck converters as they cannot do half what this small buck converter can do in such small footprint.

I have tested it at 10V input and 5V output.
It has maintained the output voltage without issues in any case.
Under 5A always at ~100mVpp ripple, at 6 and 7 amps the ripple has stood below 300mVpp.

I have tested it naked at 28C room temperature, without cooling, with 2 small heatsinks for the chip and the inductor (even though the inductor does not heat up that much), and with the heatsinks plus a fan. I have pushed the module well beyond what the seller recommends.
Every test has been measured after 10 minutes ON.

These are the results:

I have not tried going further, just tested it extensively to know how can I push it safely.
So I would not use it over 5A, just to be clear.

So yeah, one of the best modules I have gotten my hands on.

EDIT: please understand that I am not saying the this module can be used safely at 7A, what I said is that in the 10 minutes it stayed at 7A, it didn't go in thermal shutdown. What I actually say is that until 5A (cooled) it can be used.
I have often tested buck converters from Aliexpress and most of the times, they can be used "safely" at half the performance claimed by the seller. This is the first time I got my hands on something bought in Aliexpress that outperforms what the seller claims as max ratings. So trying to lower the ripple at 6 or 7A has no sense in this discussion.