This crystal oscillator is indicated for the calibration of IF steps of common radio receivers. The transistor admits equivalent as 2N2222 or BF494. The circuit is from an old American publication.
We found this circuit in an Electronic Design from the 80's. The generated tone can be changed as well...
In the figure we have an oscillator circuit by Wien Bridge (Wien Bridge Oscillator). The frequency of...
We found this circuit in Intersil documentation from the 1980s. The circuit applies to other...