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.
Using neon lamps, this regulator was found in a1969’s documentation. The lamps are types available...
In the figure we have the power supply for the 8 W amplifier in the previous circuit. The circuit...
We found this circuit in the April 1988 issue of Radio Electronics magazine. The circuit can be...