This elaborate mixer is from an Electronics Today International from the 80s. Operational amplifiers are common and resistors with no value determine the gain of the amplification steps.
This circuit, which operates between 7 and 30 MHz, was found in Radio Electronics from the 1980s....
This circuit was found in an old American magazine for radio amateurs. The circuit is based on a...
This low current circuit allows the regulation of voltages in the range of 0.5 to 30 V. We find it...