This circuit was obtained from an 80's EDN. The components used are still common. The circuit can be used as a shield and the frequency is approximately 775 Hz.
This circuit was adapted from an Italian publication that no longer exists. This is “Onda Quadra”...
This circuit was obtained in an Electronic Engineering of the 90s. The operational amplifiers and...
The basic component of this circuit is a general-purpose SCR. The voltage is according to the...