This configuration appears at several points in this section, obtained from different sources. This is from American documentation. The gain is 20 and the transistor can be a BC549.
This is the basic full-scale circuit of an LM3914 for voltage measurement or voltage triggering and...
We found this circuit in the October 1992 Radio Electronics magazine. The frequency is given by C1...
Although most common piezoelectric transducers have a reduction in performance at frequencies...