This circuit was suggested by Motorola in a 1980s publication. It is based on a PUT that is not a common component today. The division depends on the capacitor values according to the table.
The diodes of this circuit are general-purpose, and the base resistors are typically between 2k2...
This electronic Morse key was found in a Popular Electronics from the 90's. The components are common,...
This well-known oscillator configuration that produces a siren sound when pressing CH1 is from a...