Found in a 1970 documentation, this circuit makes use of 741 operational amplifiers that are common today. Note that the power supply must be symmetrical.
Found in a Popular Electronics of the 90s this configuration can be seen elsewhere on our site....
This circuit is intended to indicate the operation of transmitters with powers above 5 W. The...
We found this circuit in the December 1994 Electronics Now magazine. The worthless components are...