The purpose of this circuit is to convert a short-lived pulse into a negative rectangular pulse. The circuit uses a unijunction that can be replaced by an equivalent such as 2N2646.
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...