This circuit is from Motorola documentation, but can be implemented with virtually any phototransistor and any general-purpose transistor. The supply voltage can also be changed.
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....