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.
The circuit presented was suggested by the National Semiconductor's Linear Applications Handbook of...
This is the normal configuration for an oscillator with a tunnel diode. The crystal determines the frequency...
This balance indicator for stereo amplifiers was found in an 80's Elektor. The components used are...