A motley collection of ideas
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
The purpose of this project is to extend the range of an older (and more affordable) frequency counter into the VHF and UHF bands. The idea was inspired by an article published in Rádiótechnika (1990/7, pp. 341–342), although the original circuit was designed by Zeljko Bozic, S52ZB, and later published in a 2006 issue of … Read more
I built this inductance meter adapter a long time ago for use with a digital multimeter capable of frequency measurement. The basic idea came from an article published in Funkchau issue 1/1981. I slightly modified the original circuit and designed a new PCB. Of course, I no longer use this device for measuring coils today, … Read more