This simple metronome, from 1985 documentation uses only transistors and has two settings. For voltages above 6 V, up to 12 V, replace the BC557 with a BD136.
We found this circuit in a 1970 publication by General Electric. The components can be changed...
This source is used to supply circuits with operational amplifiers, being originally created for...
Suggested by American documentation from 1968, this circuit divides the frequency of synchronized...