Reddit:Electronics

I had an awful lot of power outages lately and decided to make a lamp based on a 12V 10W LED I had laying around. It is controlled by a dimmer with a 555 timer, modified by connecting the reset pin to a switch. This gives the devices 3 modes - off, on, or triggered by a motion sensor. I am quite proud of myself for figuring out the motion activation without using an MCU.

The device is powered by any qc/pd device via a trigger or an external battery.

And yes, it would be better with a 3d printed case, but I had to move and couldn't take my 3d printers with me yet, so this one is held together with hot glue and hope for a better future cardboard.

I can never keep this clean, its one thing after another.

It would've been a shame if it was domestic

Just cleaned up and reorganized my small bench setup yesterday and thought I could get some critiques on what might be missing. not shown is a HP 8592 Spectrum analyzer and HP 54615B 500 MHz OScope.

I used the TL431 reference programmable zenner with an emitter follower for extra stability. This takes my ±38V and makes a ±15V helprail to power op amps etc. Think i hould be able to draw 500mA-1A current on the help rail!. One more step closer to finish my linear dual rail build ±0-35v, 2.2A per rail total 4.4A.

A year ago, I worked at a workshop that specialized in rewinding electric motors and transformers. We frequently received motors and transformers for maintenance and rewinding, but sometimes we received DC motors that typically operated with a 400 V DC stator and a 200 V DC armature.

To run and test those motors, our power setup was quite cumbersome. We would connect 400 V AC to a large motor-generator set, and the output from that would power the DC motor's stator. For the armature, we took a single-phase 220 V AC line, passed it through a bridge rectifier, and then controlled the voltage using a Variac before finally feeding it to the armature.

This entire process was bulky. It inspired me to design a power circuit capable of electronically controlling the armature voltage, which is essential for modulating the motor's speed. Unfortunately, I never got the opportunity to implement the circuit. The owner of the shop, who was also my electrical machines professor at university, was an elderly gentleman who passed away, and the project get stalled.

Recently, I've been experimenting with the circuit in simulation and found it can be used for several interesting applications:

• High-Voltage (HV) Switch
• Linear Regulator
• Step-Down (Buck) Converter
• Step-Up (Boost) Converter (A topic from a previous post)
• I'm also confident it could be used to build a audio driven signal modulation ( weird but possible ).

My biggest worry was the power that the IGBTs would have to sustain. If we assume the voltage drop across the IGBT (VCE​) is around 100V (the point of maximum power dissipation), the IGBT would need to dissipate about 450W of power.

I was highly concerned about whether a single IGBT could handle this continuous load without failing. I was planning to mount the transistors onto a large aluminum heat sink block and place several IGBTs in parallel to distribute the power load among them.

Anyway, I wanted to share this project with you. here The diagram for circuitJS.

$ 1 0.000005 10.20027730826997 49 5 43 5e-11 t 320 192 320 144 1 -1 195.0523838167561 -0.7316787632313719 100 default f 336 240 336 192 40 1.5 0.02 w 176 144 304 144 0 R 176 144 96 144 0 0 40 200 0 0 0.5 t 256 416 176 416 0 1 0 0.47551466520158947 100 default t 256 416 336 416 0 1 -5.6784882330384585 0.47551466464471304 100 default w 256 416 256 384 0 w 176 384 256 384 0 w 176 400 176 384 0 r 336 432 336 512 0 100 w 336 512 176 512 0 g 176 512 112 512 0 0 w 336 144 352 144 0 r 432 432 432 512 0 100 w 432 512 336 512 0 w 432 432 432 336 0 w 432 144 560 144 0 r 560 144 560 512 0 22 w 560 512 432 512 0 p 688 144 688 512 3 0 0 0 w 560 144 688 144 0 w 688 512 560 512 0 r 432 144 432 240 0 1000 r 176 432 176 512 0 100 r 176 240 176 144 0 10000000 w 176 288 176 240 0 w 176 320 176 384 0 w 176 240 336 240 0 w 336 240 336 400 0 w 352 192 352 144 0 w 432 240 432 272 0 w 432 144 352 144 0 w 432 272 384 272 0 w 432 336 432 320 0 t 384 304 432 304 0 1 0 0.6259000454766762 100 default w 432 272 432 288 0 w 384 272 384 304 0 t 384 304 176 304 0 1 -5.2027187673209605 0.47576946571749795 100 default o 19 32 0 4098 320 0.1 0 1 38 22 F1 0 1000 100000 -1 Resistance

The ITS1A display tube is a bit of a mystery since it is poorly documented and little is known about the application for the tube. It was manufactured by the Soviet Union at the height of the Cold War when LEDs and VFDs were readily available. But, why then was it developed? It may be these tubes were developed for SW radio applications since their internal ‘multiplexing ‘ capability yields little or no EMV to interfere with weak signal reception. OR, unlike nearly every other neon display, which require control signals in the hundreds of volts range to activate, the ITS1A can be connected directly to a micro-controller and run with TTL level 5 volt signals. This is possible because the ITS1A contains seven tiny thyratrons, one for each segment, which perform the level shifting to control the 300 volt signals needed to ionize the gas inside the tube. The ITS1A is also unique in that it is a neon tube that does not glow amber like all other cold Cathode tubes, instead each of the tubes display segments is a phosphor-coated cup that illuminates green by electron spatter from the control thyratrons. In operation and when viewed from the side this beautiful little tube actually presents in three colors; pink/purple from the neon ionization, a little bit of blue from the electron paths inside the thyratrons, and from the front, the segments glow a beautiful cyan/green from the phosphor coating

Found this beauty for 30bucks ! The owner was an Thomson enginner 30years ago. Bit of dust inside, im planning to restore it ! Its huge ! Around 20kg !

Hey everyone!

I've been diving into some high-voltage (HV) power electronics experiments recently. I wanted to share a project I've been tinkering with: a custom step-up converter.

We all know that step-up (Boost) circuits are excellent for boosting low-voltage inputs (like 12V), but I had a different idea: what if I use the Boost topology on an already high DC voltage?

My goal is to take a 100V DC input (or ∼167V DC if I rectify and filter a 120V AC line) and significantly boost it.

I'm currently deep in the simulation phase and plan to build a physical prototype soon. I'm looking for feedback from anyone experienced with HV DC/DC conversion on my approach.

here is the diagram for circuitJS:

txt $ 1 0.000005 3.046768661252054 50 5 43 5e-11 w 752 0 752 32 0 w 752 -32 752 -128 0 f 928 -16 752 -16 32 1.5 0.02 w 752 32 752 48 0 w 704 32 752 32 0 w 704 64 704 32 0 w 752 192 816 192 0 w 752 80 752 144 0 r 752 144 752 192 0 100 t 704 64 752 64 0 1 0 0 100 default g 560 192 528 192 0 0 w 752 192 688 192 0 r 816 -64 816 192 0 22 w 560 80 560 96 0 w 560 48 560 32 0 t 704 64 560 64 0 1 0 0 100 default w 560 192 688 192 0 r 688 144 688 192 0 100 r 560 144 560 192 0 100 w 560 96 560 112 0 w 624 96 560 96 0 w 624 128 624 96 0 t 624 128 560 128 0 1 0 0 100 default t 624 128 688 128 0 1 0 0 100 default r 560 -64 560 32 0 10000000 w 704 -64 704 -144 0 R 560 -64 512 -64 0 0 40 100 0 0 0.5 f 688 32 688 -64 40 1.5 0.02 l 560 -64 672 -64 0 0.1 0 0 d 672 -64 672 -128 2 default c 672 -128 560 -128 4 0.000009999999999999999 0.001 0.001 0.1 g 560 -128 528 -128 0 0 w 672 -128 752 -128 0 w 816 -128 816 -64 0 w 688 32 688 112 0 w 688 32 560 32 0 g 704 -144 704 -176 0 0 w 816 -128 752 -128 0 w 1088 0 1104 0 0 w 1040 0 1088 0 0 w 1088 -160 1088 0 0 r 1280 -160 1088 -160 0 3300 w 1280 -32 1280 -160 0 w 1280 -32 1232 -32 0 w 1232 -128 1232 -64 0 w 1168 -128 1232 -128 0 165 1104 -96 1120 -96 6 0 R 1040 -128 1008 -128 0 0 40 5 0 0 0.5 w 1040 -128 1168 -128 0 r 1040 0 1040 -128 0 1000000 g 1040 96 1040 112 0 0 c 1040 32 1040 96 4 3e-7 0.001 0.001 0 w 1040 32 1104 32 0 w 1040 0 1040 32 0 w 1280 -32 1280 192 0 w 1280 192 928 192 0 w 928 192 928 -16 0 w 1040 96 1200 96 0 w 1200 96 1200 64 0

Went to a local electronics store to buy some knobs and things, I mentioned dot matrix printers to an employee and he pulled one out of his butt (the back of the store) and gave it to me for free!

Felt like I had to make the serial connector myself to go with the retro feel, so I did!

My Mom always kept these safe, I learned the habit of collecting them from my Dad.

The custom pcb for my LoRa radio just arrived, sorry for the burnt mouse pad, i apparently like to solder over it😢

Found in an Apple IIe power supply. Never seen this before, but it seems to work! I didn't know you could solder to aluminum like that.

It's basically two DF Players, one plays a metronome track (prog rock, so not constant time nor signature) and the second a backing track for the songs that have it. Each output is stereo, and has a signal led with an LM393 comparator, with the set point done by the ESP32 DAC.

Next I'll implement the MIDI part to be able to change settings in my keyboard with time stamps. Probably will make a html configuration page to select various parameters.

I been using it for a couple of rehearsals and tomorrow will meet the stage.

Opened an Olarm today and found the LTE antenna lying loose in the case. This board uses a Quectel EG915N LTE module with a little SMD PCB antenna soldered directly to the board. The RF pad ripped clean off the PCB.

Ended up doing my first ever micro-soldering repair:

scraped the RF trace

destroyed it

scraped a new section

rebuilt the missing pad using one tiny copper strand

lost that strand repeatedly

reflowed the antenna back on with hot air

prayed

It actually works. I don’t know whether to feel proud or traumatised.