A motley collection of ideas
Homemade circuits, experiments, tinker-friendly electronic ideas, and and things related to amateur radio.
Vintage radios are more than just functional electronics — they’re beautiful pieces of design history. From rich bakelite cabinets to finely woven speaker cloths, every detail was crafted to be both functional and elegant. But when it comes to restoration, some of the most iconic details can be the hardest to replace — especially the … Read more
The other day, I explained to my partner how a fluorescent starter works and what the ballast is for. I won’t go into it now—if you’re interested, look it up. I also explained why electronic ballasts are supposedly better than traditional ones. Well, I was wrong: they aren’t better. Every self-respecting electrician or hardware supplier … Read more
In Hungary, the use of radio frequencies is regulated by the National Media and Infocommunications Authority (NMHH). The NMHH has published the National Frequency Allocation Table and Frequency Use Regulations. Radio Frequency Bands Abbreviation Frequency Range Wavelength ELF 3 Hz – 30 Hz 100,000 km – 10,000 km SLF 30 Hz – 300 Hz 10,000 … Read more
A quartz crystal equipped with electrodes behaves electrically like a resonant circuit with a high quality factor (Q). With its help, oscillators of high frequency stability can be built. Quartz oscillators are now widely used as frequency or time standards in processors, microcontrollers, radios, and quartz watches. Oscillators An electronic oscillator is a circuit that … Read more
Manufacturers strongly advise against attempting to “recharge” disposable alkaline batteries. They claim the cells may leak corrosive electrolyte or the gas buildup during charging could cause explosions. Yet, these batteries can in fact be regenerated, which significantly reduces environmental impact and saves money. The regeneration of alkaline batteries is an old topic; even in the … Read more
Back in our Pioneer days, many of us soldered with a Czechoslovak “instant soldering iron,” for which we bent the tip ourselves from stripped copper electrical wire. Today, a single tip for a modern soldering station costs around €3–5 HUF, so it’s not wise to waste them carelessly! There are plenty of guides online about … Read more
Bats normally hibernate during the winter, but nowadays, thanks to the mild winters, we can encounter bats even in January. The real bat season, of course, begins in March–April and lasts until the end of October. This is the best time to go bat-hunting. In urban environments, the most common species are the serotine bat … Read more
In 1983, Rádiótechnika magazine published an article about a clock built around the TMS1122 IC. I redesigned the circuit and the PCB somewhat, then built it. It served continuously for 27 years, essentially without being turned off. Due to lack of space, I recently scrapped it, though it was still in working condition. The Clock … Read more
Fluorescent lamps are becoming less and less fashionable these days, as LEDs are pushing them out—but they’re really not that bad. The technology improved a lot between the 1970s and 1990s: the unpleasant light of old fluorescent tubes is a thing of the past. Flickering and color distortion have been reduced so effectively that in … Read more
I inherited this device from my father—he brought it from the Soviet Union at some point. It was manufactured in 1974 and is a typical example of the simple yet extremely robust Soviet devices. It doesn’t contain any “smart” electronic circuits, so there’s nothing in it that could burn out or break. It’s simply built … Read more