This current meter with many scales was found in a 80s American documentation. The operational amplifier is from that time, uncommon nowadays.
This circuit was found in an old Linear Technology documentation. The working principle can be...
Scratch is the scratching noise that occurs on old, scratched discs and the rumble is the...
This 6-transistor receiver was manufactured in Japan in the 60s. The circuit is superheterodyne and has a 6V...