Metronome using operational (CB22060E)

We found this circuit in an English publication. The transistor can be BC549, and the power supply can be between 5 and 9 V.

3-Bit A-D Converter (CB14253E)
This circuit was found in the Linear Applications Handbook by National Semiconductor. It uses...
1-quadrant logarithmic converter (CB7333E)
This temperature compensated circuit was found in a Popular Electronics from the 90s. Integrated...
Monochannel Remote Control Receiver (CB18340E)
This circuit can operate with 27 MHz transmitters, having been found in a Japanese publication from 1967....