This Wien bridge oscillator circuit uses a Texas Instruments 709 amplifier. It was found in an article in the September 1972 issue of Radio Electronics magazine. It is powered by a 24 V voltage.
This circuit is from 1977 documentation, but can be assembled with BC548 for Q1, Q2 and Q4, BC558...
Found in American documentation from the 90s, this circuit uses components that are still common...
This high impedance input amplifier is suitable for the use with piezoelectric sources such as...