This interesting 1924 triode tube receiver was found in a documentation by Gernsback. Observe supply voltages. Coils are for tuned wavebands.
This circuit was found in a 1999 publication. Its purpose is to flash two LEDs according to the...
This two-transistor emitter-coupled oscillator circuit with capacitive feedback was found in the...
This circuit is from an old operational amplifiers manual. However, the setting applies to modern...