Reddit:Electronics

Zener voltage = 5.1 V, Input voltage = 9 V, Resistance = 500 ohm

Late 90s before Ethernet control was anywhere near affordable and circuit control over the Internet was sci-fi dreams here was a $20 external HP JetDirect print sever controlling 8 GPIOs with Opto22 SSRs and a little fool logic to make the print sever think its connected to a real printer lol the NAND gate fooled the JetDirect that every time a byte was "sent to the printer" the printer flapped strobe as if it has printed the bye :) Data was piped via good old Linux NetCat - wait using Linux in the 90s...oh I'm getting emotional already

I’ve so forgotten those days of badass innovation - now smart plugs are everywhere …

Sorry for light getting in the way of appreciating the full beauty of this PCB :))

Wish I had a spec sheet on this part. This was pulled from an Apple IIgs monitor. I don't think it's a true led.

Works lovely on 5v

I've assembled this 4 bit full adder with logic ics.

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 !