This JFET amplifier stage was found in the Encyclopedia of Electronic Circuits Volume 5 from 1995. Any JFET can be used and the bias controlled externally.
This is a combined circuit of tone generator and preamplifier. We found it in a 1975...
We found this simple alarm circuit in a 1986 documentation. The circuit uses sensors of the NA...
We found this circuit in the Linear Applications Handbook by National Semiconductor. The base is...