This transformerless circuit was obtained in a 1965 publication by Ferranti. The components are from that time, with emphasis on the type of engine used.
We found this circuit in a publication from the 1970s. It produces intermittent clicks on a...
We found this circuit in a Philips documentation from 1969. It makes use of transistors of the...
This circuit was found in a 1999 English magazine, but can be easily assembled with BC548...