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.

Resistive Sensor LED Control II (CB1299E)
This simple circuit controls the brightness of an LED from LDRs, NTCs, PTCs or other resistive sensors....
Sound Roulette (CB16966E)
We found this circuit in a 1990 documentation. It draws one out of 10 numbers and during the draw...
Sawtooth generator (CB23731E)
The circuit shown in figure 3 uses a programmable unijunction transistor (PUT) of the BRY39 type...