This circuit was obtained in a Popular Electronics of the 90s. The circuit uses integrated from the time, uncommon today. Note that the speaker has a higher impedance than ordinary speakers.
Found in a 1970 documentation, this circuit makes use of 741 operational amplifiers that are...
We found this automotive alarm circuit in a 90's Popular Electronics circuit. The circuit emits a...
This circuit source a voltage proportional to the number of the input pulses. The circuit has a...