Phone amplifier stage (CB22485E)

This circuit is from a 1966 documentation. The transistor is made of germanium of the time and the headphone can have from 600 to 5000 ohms.

Electronic Dice (CB12221E)
This TTL dice is from an old publication from 1978, but it can still be assembled, as the...
Full wave rectifier (CB9455E)
This precision signal rectifier was found in an Electronic Design. The components used are from...
OR gate LM3900 (CB14200E)
We found this setting in the National Semiconductor Linear Applications Handbook. The base is an...