This circuit was found in an American documentation from 1975. The components of the time can no longer be found easily, but they can be tested equivalent.
The LM1468L can also be used. The circuit is from Motorola's Linear Interface ICs and the...
We found this light-effect circuit with LEDs using the well-known 4017 in a 1987 documentation. All...
This circuit was found at Popular Electronics. The speaker is of the greater than 100-ohm...