This circuit was found in a documentation of the 80s, having didactic purpose. For R1 values between 10k to 1M can be used. Transistors are general purpose types.
This circuit has a traditional configuration explored in several other points of this site. The...
We found this traditional flasher configuration in a June 1969 Radio Electronics magazine. SCRs...
This circuit was obtained in a 1979 publication. The operational amplifier is of the type with...