This direct-coupled amplifier was found in Mullard's 1960s transistor manual. The transistors are germanium from the time.
Used with infrared remotes at the time, this circuit was found in a 1991 RE Experimenter Handbook....
The output transistors can be BC548 and BC558. The circuit is from a 1975 documentation showing a...
This negative ion generator was found in a 90s Popular Electronics. The autotransformer can be an...