Bilateral current source 2 (CB20819E)

We found this circuit in an American publication from the 1980s. Equivalent modern operational amplifiers can be used.

Wattmeter (CB23581E)
This circuit is from a Radio Electronics magazine from December 1958. The indicator instrument is analog...
Wireless Microphone AM (CB16412E)
This circuit sends signals to a shortwave radio (range 3 to 7 MHz) at a distance of a few tens of...
Photo controlled triac (CB8312E)
This circuit was found in an Electronics World of 1968. It can be applied to any modern triac and...