Found in an April 1977 Radio Electronics issue, this circuit uses the well-known XR2206. The C1 values for the various frequency bands are given next to the diagram.
A The adjustable Q-factor rejector filter in the figure is based on two LM110. These integrated...
This circuit can be powered by a voltage of only 2.5 V. Next to the diagram we have the formulas...
This circuit with a supply voltage of only 2.5 V was found in a 2005 Linear Technology...