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 low-pass filter was found in Intersil documentation from the 1980s. The circuit makes use of...
The touch sensor of this circuit consists of a single plate that must be touched to obtain an...
This circuit is from an old manual of operational amplifiers. The setting can be adapted to work...