The CA3020 integrated circuit was one of the first commercial types, sold in the 1960s. The circuit presented is from 1968 using a power stage with RCA transistors of the time.
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...