RBGT-62 Geiger counter (radiac)


RBGT-62
Description: Czechoslovak military Geiger counter.
Manufacturer: ČSLA
Made in year(s): early 1960s
Country of origin: Czechoslovakia
Status: Working, last calibration April 2004… [read more]

Siemens Nixdorf PCD-4ND


SNI PCD-4ND front
Description: A laptop notebook computer.
Manufacturer: Siemens Nixdorf Informationssysteme AG
Made in year(s): 1993-1996, my model in 1996
Country of origin: Germany
Status: Working, in good condition… [read more]

Uncategorized experiments

A handful of photos and comments regarding some of my unfinished, abandoned, failed or likewise hilariously stupid experiments, for which I have gathered up the courage to put them on-line 🙂… [read more]

My vacuum tubes collection

A small selection, though being a non-collector myself, of some of my vacuum tubes (valves) that I have, or had at home, or which I had used in my circuits!… [read more]

8-stage Cockroft-Walton/Villard cascade multiplier

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.… [read more]

Semiconductor free Geiger Counter

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… [read more]

TESLA ARF 300 headphones



Description: Stereo 2x 200Ω headphones.
Manufacturer: TESLA Valašské Meziříčí
Made in year(s): 1980s
Country of origin: Czechoslovakia
Status: Left driver speaker not working… [read more]

EDOS high-range dosimeter



Description: Czechoslovak cumulative γ dosimeter.
Manufacturer: ČSLA
Made in year(s): 80s, my model in 1982
Country of origin: Czechoslovakia
Status: Working, last calibration in 2003… [read more]

MEOPTA 87328 16mm projector supply



Description: A 1200 VA transformer-based power supply.
Manufacturer: MEOPTA
Made in year(s): 1965 mine model
Country of origin: Czechoslovakia
Status: Working… [read more]

3D X-ray setup

A real-time, fluoroscopic X-ray setup of my previous attempts with the beryllium-window tube. However, radiographed objects are now placed on a slow moving turntable motor, thus creating a spectacular 3D effect, captured on camera.… [read more]

4200V high voltage supply “The Killer”

Providing output of a kilowatt long-term and in excess of 4 kVA short-term, undoubtedly it is the most powerful single-phase power supply I’ve made, and the scariest of them all! Whether you want to power up medium size Tesla coils, arc-weld through any sensitive electronic evidence or commit suicide using one of the most horrendous ways, this beast always gets the job done.… [read more]

Two watt blue laser driver 445nm

Now here’s a novelty, besides high voltage! A two watt 445nm “M140” diode in heatsinked, focusable housing, all with a regulated constant current driver. So, here’s the result of jumping on the bandwagon of lasers… [read more]

Fluoroscopy of a hand

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 or amputation of irradiated… [read more]

X-rays with a Beryllium-window tube

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… [read more]

Dual ignition coil driver

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) to generate sparks and a sturdy primary/secondary winding with appropriate insulation… [read more]

X-rays with a dental Chirana

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!… [read more]

Arcs from mains voltage 230 V

You might have seen them all. Flyback transformers, microwave oven transformers, ignition coils, oil burner transformers, potential transformers, pole pigs, x-ray transformers, high voltage switched mode supplies, Tesla coils and the list goes on. However, have you ever thought of a possibility of drawing arcs directly from mains current?… [read more]

Small Vacuum tube Tesla coil (VTTC)

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 a flat though, there would be no place to accomodate 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.… [read more]

Digital pulse counter

This here is a simple but versatile pulse counting/smoothing integrator circuit with an NE555 as the shaper, and a little LCD display as the output. I have originally done it for counting pulses from my Geiger counters, so I have included a piezo speaker combined with an LED for indication, but it can also have a variety of other applications, like revolution counters, track/lap counters… [read more]

Geiger Müller counter

This is a device which I have constructed back in 2010, when I had no calibrated radiation metering devices such as the IT-65 at hand, and there was a need to distinguish between normal and abnormal intensity levels. The reason why I have chosen to do this from scratch was simple: back then, I had quite a few GM tubes lying around doing nothing and I’d been unhappy with a conversion… [read more]

X-rays with a 6VS-1 (6ВС-1)

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:… [read more]

X-rays with a DY86

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.… [read more]

Triac phase regulator

This circuit, also informally known as the poor man’s variac, is used in many applications in both consumer and industrial electronics, where a perfectly sinusoidal waveform is not required and a real variac (variable autotransformer) would be too heavy and bulky. This is the case of light dimmers, vacuum cleaners, motor speed control, heater elements and similar. It was… [read more]

Central heating pipe antenna for SW

If you happen to live in a flat with steel central heater pipes and you don’t have the option to make yourself an external antenna, due to e.g. thermal insulation, this might probably be the best indoor shortwave antenna for portable world band radios; when it comes to signal (or noise) strength. The latter happens in unfortunate cases, when there are just many switched mode-based… [read more]

Flyback driver #3: ZVS

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… [read more]

IBG 58 T Radiation indicator



Description: Czechoslovak army radiation indicator.
Manufacturer: TESLA or Czechoslovak army
Made in year(s): late 50s-early 60s; 1962 was my model
Country of origin: Czechoslovakia
Status: Not available… [read more]

DP-5B (ДП-5Б) Geiger counter (radiac)



Description: Soviet army Geiger counter.
Manufacturer: Unknown
Made in year(s): mid 60s-early 80s
Country of origin: U.S.S.R.
Status: Working, last calibration March 1990… [read more]

IT-65 Geiger counter (radiac meter)



Description: Czechoslovak army Geiger counter.
Manufacturer: Rudi Čajavec and TESLA
Made in year(s): late 60s-mid 80s; 1969 is mine model
Country of origin: Yugoslavia & Czechoslovakia
Status: Working, last calibration Feb 2006… [read more]

Fully Regulated ATX Power Supply

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.… [read more]

Degen DE1103

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… [read more]

A Guide to Flyback Transformers

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… [read more]

Flyback driver #2: NE555 quasi-resonant

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 … [read more]

Flyback driver #1: Single transistor driver

Back in 2008 before starting with high voltage, I have made numerous experiments with flyback transformers and with simple single-transistor drivers, most of these were undocumented. However, this was one of my very first high voltage circuits and my first -electronic- circuits in general, which were marked with some success. The resulting simplicity of this circuit pardons … [read more]

TESLA Merkur 4160AB B&W TV



Description: A portable black and white TV.
Manufacturer: TESLA Orava, k.p. Nižná
Made in year(s): 1982-1989
Country of origin: Czechoslovakia
Status: Not available… [read more]

TESLA Moderato 1037A radio record player



Description: Two speed record player with radio.
Manufacturer: TESLA Bratislava, k.p.
Made in year(s): 1983-1985
Country of origin: Czechoslovakia
Status: Working… [read more]

380 volt circuit continuity tester

There’s always a need for a multimeter when working with electronic circuits. Especially when it comes to semiconductors. Using the internal diode test, which is now a part of every good meter, we are able to double-check the proper function of every diode, bipolar transistor and the like, before using them in our projects. However, there are still certain parts, for which … [read more]