The integrated circuit used is uncommon today. The circuit was obtained in the Philips integrated circuits manual of 1990. The reference voltage-range is from 0.5 to 9.0 V.
This transistor source was found in a 1990 documentation. 2N3055 transistors must be equipped with...
This tube circuit is from an 80's documentation. The filter is of the selective type and the...
This general-purpose two-transistor circuit was found in the November 1993 issue of Electronics Now. The...