This very high input impedance JFET circuit was found in the 1995 Encyclopedia of Electronic Circuits Volume 5. The JFET is a general-purpose transistor as is the output transistor.
This is the patent for the zener diode regulator circuit by David B. Dean of Austin published in...
This simple 10-position roulette circuit with the 4017 found a 1987 documentation. The circuit can...
This circuit was found in a 1986 documentation. The circuit has a common configuration with the...