A motley collection of ideas
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
This circuit is a simple flasher that produces strong and short flashes. If you already know how a transistor works, you’ll have no trouble understanding how this thing operates. You can find the circuit on Tinkercad here: 👉 https://www.tinkercad.com/things/jn4ZX0OA4qi-flashing-light Although it works in a very simple way, this circuit actually exceeds the capabilities of Tinkercad’s … Read more
This circuit is a simple, contactless wire / mains voltage detector. It can detect 230 V mains wiring from a distance of 10–15 cm, indicated by a red LED and a buzzing sound. You can find the circuit in Tinkercad: 👉 https://www.tinkercad.com/things/cZa2iaSgAAG-wire-tracer The L1 coil is a self-supporting air-core coil. It can be made from … Read more
A popular variant of the well-known NE555 timer IC is the NE556, which contains two timers. With this IC, you can build a simple siren. This siren alternates between two tones, similar to old police car sirens, while also flashing a blue and a red LED. You can test the circuit in Tinkercad: 👉 https://www.tinkercad.com/things/lsxjw2LzvA7-police-siren … Read more
Barches, or challah, is a traditional baked good of Jewish cuisine: a braided yeast bread or sweet roll, sometimes enriched with potato. In families that keep Jewish dietary traditions, it is a customary element of the Friday evening Sabbath table. Details Serves: 4Preparation time: 1 hour Ingredients Preparation Sift the flour into a bowl and … Read more
This is a simple sound generator that can be controlled by light or by your fingertip. If you illuminate the photoresistor with a lamp or cover it with your hand, the pitch of the sound changes. You can try it out in Tinkercad: https://www.tinkercad.com/things/aEJgBAQp91s-fingertip-organ Instead of the photoresistor, you can place two bare wires that … Read more
Who hasn’t come across that moment when a formerly leather-like, silky-smooth coating on your stuff suddenly turns sticky? If it’s just a ballpoint pen that ends up in the trash because it’s gooey, you shrug it off. But when the kitchen knife holder sticks to the tiles—or worse, your e-book reader or an expensive studio … 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