This circuit uses components of the time. We found it in a 1968 US documentation. The delay is 100 ns and the input impedance is 1 k.
This circuit was found in the January 1996 issue of Electronics Now magazine. The circuit is...
This circuit was found in a 1987 edition of the United States' Hands-On Electronics magazine. The...
This circuit is from the magazine 73, for radio amateurs, from the 80s. The circuit uses common...