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 high sensitivity of this type of SCR recommended in our assemblies allows it to be triggered by low...
The circuit presented is from the 1994 Linear Applications Handbook from National Semiconductor. The circuit...
The oscillator shown in the figure generates a 1 kHz tone that is reproduced on the speaker with...