Metal detector for medium-large objects

[dbanner]

Hi dbanner,
Thank you for this very interesting information! Just one problem - 2N5245 is very old and now it is very hard to be find. It will be useful for all us if you have possibility to test this design with J113 transistor. This type is still in production.

The input capacitance of the JFET should be as low as possible otherwise the results will be skewed. You could compensate for this in the calculation script. The circuit might still oscillate with the J113, although I have never tried those.

I used the NTE133 instead of the 2N5245 for my circuit, it works well, no problems to oscillate.

However, these might also do the job:
2N5484 / 2N5485 / 2N5486
2N3819
MPF102
BF245
J310

[Detectorist#1]

Hi dbanner,
Thank you for the answer.