This circuit using the CK722 among others came out in a September 1950 Radio Electronics. It was one of the first circuits of this type published with transistors that started to reach the market.
This circuit from the 90s, was found in an Electronic Design of the time. The components used are...
This circuit was found in an English technical documentation from 1973. The circuit generates...
The selected circuit was obtained in a Texas Instruments opto-electronics manual. The transistors can be...