We found this circuit in a 1977 factory documentation. The operational amplifiers can be 741 and the symmetrical power supply. Capacitors can be changed for operation at other frequencies.
Indicated to be used at the sensor input of a PC, this circuit was found in an English...
This circuit monitors extra-low frequency (ELF) fields. We found it in an American documentation from the...
With this circuit we can use a high impedance source to excite a low impedance output. The input is...