This transistorized circuit is powered by a voltage of 6 to 12 V providing high voltage for a neon lamp. The circuit is from a 90's publication. Modern equivalent transistors can be used.
This doorbell or buzzer as announced in a 1990s US publication uses an operational amplifier that admits...
With the CMOS circuit shown, rectangular signals up to a few megahertz can have their frequency divided...
This sensitive motion sensor with inductive sensor was found in a 90s Elektor. The circuit uses only...