Old superheterodyne (T1611E)

Found in a 1949 Radio Electronics, this commercial circuit was found in many countries, including Brazil.

Crystal oscillator (CB23647E)
This circuit of various uses on the bench was found in Radio Electronics magazine from January 1960....
Power Inverter OC19 (CB18856E)
This circuit is from a 1957 Japanese magazine, showing the use of OC19 in a high voltage inverter. The...
15 V x 1 A power supply uA723 (CB19023E)
The integrated circuit used in this power supply is no longer very common in power supplies today....