The figure shows a way to apply gain control to the LM3600 OTA. The circuit is from a Radio Electronics from July 1988.
This amplifier with differential input uses two old op amps but can be implemented with modern op amps....
This power supply was found in the December 1970 issue of Radio Electronics magazine. The...
This circuit is a wireless temperature transmitter for RF signals in the range of 0.2 to 2 MHz...