This power supply for model railroad was found in a February 1961 Radio Electronics Magazine. The transistor must be mounted on a heatsink and the transformer is a 1,5A secondary winding.
This circuit was obtained in a Popular Electronics from the 90's. The gain depends on R4 and R3....
The trigger element of this circuit is a neon lamp. The SCR admits an equivalent. We found it in...
This circuit for the power grid was found in the June 1969 Radio Electronics magazine. The SCR and...