This is one of the many versions of this type of indicator that the reader can find on our website. This is from Mullard's 1969 documentation. The indicator is 95 uA (100 uA).
This high Q “rejector” or notch filter rejects signals whose frequencies are in the range...
This circuit was found in documentation from the 90's, having an LC compensation network. The...
This two-transistor circuit was found in the January 1994 issue of Electronics Now magazine....