R1 may be 10k and R2 100k. The transistor can be the BC548 and instead of the small lamp we can use a series LED with a 1k resistor. D1 is germanium and C1 is 10 nF. C2 can be 47 nF.
This low-noise hydrophone circuit was found in a 1980s Linear Technology component manual. The...
This circuit for 40 V systems was found in a Linear Technology application manual. The circuit...
This circuit was found in an ancient American documentation. The integrated circuit is of the time...