This traditional circuit generates a 200 Hz sinusoidal signal. The frequency depends on the capacitors and the transistor can be a BC548. We found this circuit in a 1979 documentation.
This 1967 Electronics World circuit is suitable for frequencies up to 1 MHz. The setting applies...
Connected between an external antenna and the antenna input of a receiver, this circuit provides...
The purpose of this circuit from a 1995 publication. Its purpose is to alert a person when he...