Found in an old Popular Electronics this circuit is still current. The SCR can be of the 106 series and the relay according to the voltage used in the supply. The voltage can be 12 V.
This circuit is from a Poptronics, American magazine of August 2000. The circuit can be assembled with...
This is the normal configuration for the TDA2003 integrated circuit, an amplifier that can provide 10...
This stabilized source can supply currents up to 700 mA and the output voltage is close to 15 V. a...