This 555-based circuit was obtained from the 1995 Encyclopedia of Electronic Circuits volume 5. It triggers an SCR when the transistor is cut off.
We found this function generator with two FET operators in a 1996 Texas Instruments application manual....
This circuit was obtained from an English magazine from 1979, but can be easily assembled today...
The integrated circuit used in this 2002 project is not very common. It is powered directly by the...