Music box (CB8626E)

This circuit was found in a 90s Popular Electronics. It uses an LS3404 melody chip that has several recorded melodies and that is uncommon nowadays.

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Time delay (CB23969E)
This circuit turns on a lamp after the time set on the potentiometer. The circuit is from a Radio...
Switching for EMG (CB7373E)
This circuit was obtained in documentation on medical applications from 1966. The circuit is used in...
Voltage Follower with the CA3140 (CB12304E)
In a voltage follower, the voltage gain is unitary, the input impedance is very high, and the...