Medium impedance stage (CB20563E)

We found this circuit in an English publication from 1963. The circuit uses germanium transistors of the time.

RS232 temperature interface (CB21278E)
Found in an Electronic Design from the 90's, this circuit uses common components. The circuit is...
1 W Amplifier (CB18192E)
This good quality amplifier found in a 1982 documentation has a traditional complementary output...
Adjustable Zener With Transistors (CB18938E)
The transistors in this circuit can be BD135 and BD136 for currents up to 500 mA. The circuit...