This conventional circuit is from Motorola's 1993 Linear Interface ICs. The power source must be symmetrical.
Using 4 operational amplifiers this circuit generates 4 different tones. The circuit is from an...
Found in a 1966 documentation, this “coin finder” uses components from the era operating at 2.1...
We have here a simple signaling circuit for two common incandescent lamps, which is used for...