This circuit was found in a 1967s Motorola documentation. The circuit regulates the voltage of an alternator for automotive use, for bench applications.
This is the circuit of the commercial Japanese megaphone of the 60s model DM-218. The circuit uses...
This circuit was found in a 1973 Radio Elettronica magazine from Italy. The circuit can be...
I found this circuit in an old Argentine publication from 1973. The components are no longer...