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.
September 2016 - can already be purchased at Mouser Electronics the Robot Scribbler S3 from...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
This simple transistorized game that appears in other versions in this section and website, was...