The integrated circuit used in this application is not currently common. The circuit is from 80s documentation. The power depends on the controlled load.
This is a traditional 741 configuration with gain close to 100. We found it in the December 1972...
This sensitive circuit was found in the June 1995 Electronics Now magazine. R1 can be from 10k to 1M...
This astable multivibrator, well known to all, was found in the Raytheon transistor application manual of...