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.

| Clique na imagem para ampliar |

FET and Bipolar Voltage Follower (CB13391E)
Obtained in an American documentation from 1976, this circuit has a constant current source for...
One Transistor Voltage Regulator (CB20178E)
The output of this voltage regulator depends on the zener diode. The current depends on the...
Shadow Relay (CB1305E)
This well-known circuit triggers a relay when light striking the phototransistor is cut off. The...