This circuit was found in a 1967 Electronics World. We can design it with a BF245 for the FET and a BC558 for the bipolar transistor. The circuit has 3 scales and a 10 M ohm input resistance.
This circuit is designed to activate an automotive alarm after 8 minutes of activation. Of course...
This is one of the channels of an amplifier suggested by Westinghouse in 1970s documentation. The circuit...
This astable multivibrator, well known to all, was found in the Raytheon transistor application manual of...