Found in a 90s Popular Electronics, this mixer can be expanded to more channels. Transistors can be modern general-purpose equivalents.
Found in Motorola documentation from 1967, this circuit shows how it is possible to obtain a...
We found this circuit in a Popular Electronics from the 80s. This circuit eventually doesn't work with...
Pressing S1 by a moment L1 glows up, remaining by a time interval depending on C1. This time...