The transistor used in this circuit is uncommon today. AC124 or equivalent such as AC188K and 2N2431 can be used. The circuit is from the 80's and makes use of transformers.
Found in an Electronic Design from 1968 this circuit generates a linear sawtooth signal modulated...
This shortwave preselector was found in the July 1994 issue of Radio Electronics magazine. The...
This circuit is based on an operational amplifier that must be powered by a symmetrical source. The...