This commercial signal follower was found in a 1967 Japanese magazine. It uses germanium transistors and provides a speaker output without the need for a transformer.
This circuit was found in a Popular Electronics from the 90s. The frequency depends on the...
This circuit consists of a “zero crossing detector” that provides a rectangular output signal...
Low power RF transistors such as the BF494 or BF495 and even those in the BC series can oscillate well...