This circuit has an accuracy of 1%. The components used must be precision as well. The input frequency range is 40 Hz to 10 kHz with the indicated components.
This circuit was found in an English publication in 1986, but it can still be implemented by...
This traditional configuration is from a 1976 publication, showing that nothing has changed since...
This circuit is more elaborate than the previous one, employing an integrated amplifier circuit of the...