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.

Sinusoidal and Rectangular Oscillator (CB19259E)
This audio generator that produces both rectangular and sinusoidal signals was found in a...
One -Transistor AM Radio (CB1343E )
This simple circuit for a high impedance magnetic phone (500 ohms or more) has been found in a...
Control for miniature railways (CB7079E)
Found in an American publication from 1968, this circuit can be made based on a TIP42 that must be...