Telephone dialer (CB9235E)

This circuit was obtained in Radio Electronics from the 90s. The integrated circuit is uncommon today.

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Transistor Tester (CB4370E)
This circuit was found in an English magazine from 1979. The magazine no longer exists, but the...
Debounced Switch 7404 (CB3861E)
This traditional TTL anti-clock setting was found in a 1993 American documentation. The circuit...
Low Frequency Astable (CB470E)
The astable multivibrator shown by the figure can produce signals in the 10 to 10 000 Hz band...