This toy transistorized organ was found in the May 1970 issue of Radio Electronics magazine. The trimpots are adjusted to the musical notes according to the key.
This circuit, with a 12 V input, was found in a Popular Electronics from the 1990s. Information is given...
This circuit is the equivalent of the CB121, but is triggered with the negative transition of the...
We found this circuit of a clamp-type ammeter in a Japanese documentation from the 1960s. The...