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.

Function Generator 566 (CB19526E)
This circuit found in a European publication from the 1980s, is based on PLL 566. The frequencies...
1 A symmetrical power supply (CB25954E)
The circuit shown, with the printed circuit board, was found in an article in the June 1990 issue...
Timer (CB5978E)
In the figure we have a simple timer with two voltage comparators of the four of an LM339. The...