Telephone dialer (CB8521E)

Using an integrated circuit from the time, we found this configuration in a 90s Radio Electronics.

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Ultrasonic repellent (CB8103E)
This circuit is from a PE Hobbyst Handbook from 1991. The integrated circuit is a common 555 and...
Emergency Light (CB1561E)
With the configuration shown in the figure, a common 12 V lamp lights up when light no longer...
Bargraph Peak Detector LM3915 (CB14385E)
This circuit was obtained in the National Semiconductor Linear Applications Handbook of 1994. The...