We found this circuit in an old documentation. The operational can be of any type and the frequency is given by the formula next to the diagram.
This amplifier can be used for public-address or other applications. Three transistors of the time...
This circuit was found in a 1967 Electronics World. The circuit uses components of the time that...
This circuit was obtained in a June 1987 magazine Hands-On. It is a circuit that indicates on an...