Bench thermometer (CB20501E)

With an ultra-low consumption, this circuit can be powered by solar cells. The circuit is from a 1991 documentation.

Bistable relay (CB7159E)
Found in a Hands On Electronics from the 80's, this circuit activates a relay with alternating...
Biphase VCO 4046 (CB25249E)
This circuit generates signals with opposite phases determined by C1 and adjusted by R2. The...
Optical control notch filter (CB6717E)
This 1967 Raytheon circuit uses an optical coupler of the era and has a range of 800 to 200 Hz....