The transistors of this circuit found in a 1965 magazine can be the BC558 and the sensitive 12 V x 50 mA relay. The other components are common.
This reflex receiver for the mid-wave range employs germanium transistors of the time. We found it in...
Using a 106 series SCR, this circuit was found in the May 1971 Radio Electronics magazine. The...
This circuit was found in an old manual of linear integrated circuits of the 80's. Equivalent...