This 3-step circuit for generating digital signals was found in the November 1976 issue of Radio Electronics magazine. The maximum frequency depends on the flip flops.
I found this circuit in an English magazine from July 1982. The circuit is still viable by using...
The circuit shown was found in the 1994 National Semiconductor's Linear Application Handbook. The...
This solar powered circuit was found in a 1991 documentation. The transistor is a general purpose...