Two-tone solar buzzer (CB20493E)

This circuit was found in a 1991 publication. The transistor can be a general-purpose type.

Dual Limit Comparator (CB5074E)
This circuit was found in an American 80's documentation. The operational may be a modern type...
Series JS Temperature Sensors (COM146E)
November 2016 - The new self-adhesive surface temperature sensors of the Amphenol JS series can...
Voltage and Current Regulator (CB5876E)
We find this circuit in a manual of the 80's own used components. The circuit provides an...