Flyback driver #2: NE555 quasi-resonant

- High voltage

This single transistor flyback driver topology was created in response to achieve higher efficiency and higher output voltages from ordinary CRT television flybacks (diode split flybacks), for experiments such as x-rays or ionic lifters, without having to make any external HV multipliers. Since these flybacks are normally sealed in epoxy and can withstand an output voltage … [more]

A Guide to Flyback Transformers

- High voltage

Unless professionally required, a lot of high voltage enthusiasts do not wind their high voltage transformers at home. This task would be nearly impossible to do without proper coil winding, insulation potting and vacuum-sealing machinery. Thus, high voltage transformers from everyday electronic appliances, such as CRT TVs and computer monitors, microwaves, automobile ignition… [more]

Degen DE1103

- Radio & AV

This is a great little battery powered PLL-tuned LW/MW/SW/FM receiver with support for single-sideband reception. I got it off eBay one year ago, for approx. 49 EUR including shipping. Receives 100-29999 kHz AM with SSB and FM 76-108 MHz, has 255 station presets, a backlit faux-analog display and small power consumption. I did a full review of its features on  Priyom.org as a member… [more]

Fully Regulated ATX Power Supply

- Low voltage

Now, let me begin this article by stating that this *is not* a so-called “conversion” with an LM317 (or any other linear regulator in general) like you might have seen on thousands of other web pages, nor a so-called “lab” supply that was made just by shorting the PS-ON pin. This is a real ATX to regulated supply conversion, which might come in handy for you.… [more]

Flyback driver #3: ZVS

- High voltage

The ZVS flyback driver, made popular by Vladimiro Mazzilli, is one of the most efficient and powerful flyback drivers used by high voltage hobbyists from all over the world. The main advantages of this driver are simplicity of the circuit itself, very high efficiency and easily obtainable parts. By tuning it properly you are able to get insane power outputs; beefy flyback transformers… [more]

X-rays with a DY86

- X-rays

The DY86 (DY87, DY802) vacuum rectifier was used in most European black and white tube television sets. In hot-cathode mode, it was capable of rectifying up to 18 kilovolts at 0.5 mA. In cold-cathode mode, however, it withstands 40 kilovolts DC inverse for a short time, while providing some soft X-ray radiation enough to set classic Geiger counters off.… [more]

X-rays with a 6VS-1 (6ВС-1)

- X-rays

In 2010, me having already exploited the DY86, a Czech experimenter nicknamed “DANYK” came up with an oddball Soviet vacuum stabilisator tetrode “6VS-1”, which produced copious amounts of X-rays in hot-cathode mode. He got pretty good radiographs, nevertheless. So, I have got an inspiration and obtained a few:… [more]

Small Vacuum tube Tesla coil (VTTC)

- High voltage

To go along with flyback drivers, X-rays and other high voltage stuff, I have decided to build myself a Tesla coil. Because I live in an apartment building though, there would be no place to accommodate and run monstrous coil designs, not mentioning interference, so that is the reason why I’ve opted for small and sweet portable setups like this one is.… [more]

X-rays with a dental Chirana

- X-rays

After receiving a donation of two nice X-ray intensifying screens from Mr. Máca, a Czech radiologist (many thanks!) in 2011, it wasn’t long before I got a hand on a real X-ray tube, obtained through barter trade, with some luck, too. Only then were my previous failed X-ray attempts with DY86‘s and 6VS-1‘s marked with success, at least!… [more]

Dual ignition coil driver

- High voltage

Apart from flyback transformers or MOTs, automotive ignition coils are also used as high voltage sources by many enthusiasts. Especially those classic cylinder-shaped ones, used in carbureted engines pre-1990, since these were driven directly from the battery (through contact breakers)… [more]

X-rays with a Beryllium-window tube

- X-rays

While lurking on eBay on a nice spring day of 2012,  I have been lucky to obtain a real gem, for a very cheap price indeed: a special micro-focus X-ray tube, with a Be window on the beam port, mostly for spectral analysis or fluoroscopic scanning purposes, for up to 150 kilovolts with forced oil cooling at high powers; made by a now-defunct American EG&G Astrophysics company… [more]

Fluoroscopy of a hand

- X-rays

This might be the craziest documented experiment/project on my page – a fluoroscopic radiograph of my hand, utilizing my beryllium-windowed vacuum tube setup. For the sake of your own safety and the safety of others, do not attempt to recreate without proper knowledge and protection, as hazards include radiation sickness, increased risk of cancer… [more]

Semiconductor free Geiger Counter

- Low voltage

Tried searching the keyword “geiger counter” on Google, or even better, on YouTube? Now, how many of them contained a multitude of transistors, analog microchips or even digital microprocessors, and no shielding at all? Well, whatever the count is, a majority of them – if not all – are going to fail miserably, due to a huge electromagnetic pulse, when the… [more]

200 kV multiplier

- High voltage

Something I’ve crafted for the new X-ray experiments: a half wave, eight stage Cockroft Walton multiplier (or a Villard cascade, whichever name you like), submerged in oil, providing a theoretical maximum output voltage in excess of 220 kV with a maximum supply voltage of 10 kV AC, with headroom.… [more]

Nixie tube tester

- Low voltage

This very simple circuit can be used to verify the proper functionality of each cathodes in a Nixie tube, which was the predecessor of the solid-state LED 7-segment display, back in the 1960s and early 70s. The main anode voltage is obtained from a simple, battery-powered flyback inverter with just enough voltage to strike the glow discharge, and an adjustable resistor current limiter… [more]

CRT screen regenerator

- High voltage

With a predictable demise of CRT screens that’ve been phased out of production since the late 2000s, the owners of vintage TVs, monitors or other displaying equipment, kept in a condition that’s just too good to be thrown out, will eventually bump into a problem concerning each and every CRT – or any vacuum tube in general – of decreased cathode emission, … [more]

Arduino Mega2560 nixie clock

- Low voltage

Some five years ago, I had a RepRap 3D printer setup running the Marlin firmware on an Arduino Mega 2560 board. With that long gone, I was thinking about some other projects I could try on it: a floppy drive controller, and perhaps a clock, with some neon indicators I have managed to salvage from a 1970s benchtop multimeter of Czechoslovak provenience. Even though I have to admit that it… [more]

Yaesu FT-857 CAT/interface cable

- Radio & AV

Recently I have been drawn before the commission of a local telco bureau, to take part in an amateur radio examination, by a fellow attendee. The motivation?  Well, each time I tinkered with a radio, I always skipped scanning of “ham” bands as I never really found debates regarding signal reports, the weather or their next planned doctor’s visits to be of particular… [more]

‘Cat printer’ stock ticker

- Low voltage

A while ago they’ve been airing reruns of the old black&white Addams Family series that I watched at my sister’s place. In one scene they’ve shown Gomez reading ticker tape, losing $1,000,000 just moments after he earned them, and my eyes immediately landed on a make-up brush holder my sister uses. That thing, I said to myself, looks similar to his stock ticker… [more]

Štítky panelu Tesla BM215A

- Low voltage

Hneď na úvod poruším pravidlo a nebudem písať tento príspevok anglicky, keďže je to merák našej proveniencie – nedávno som si ho dával dokopy a po odstránení technických porúch (taká tá klasika: bočníky, asfalťák, studeňáky) nasledovali tie estetické – červená indikácia v mikroampérmetri  a zošúchaný predný panel.… [more]