Hi everyone and thanks for your time.
I have an issue that is driving me mad and consuming the time my doctor says I should use to exercise...
I use this circuit in an inductive sensor, is a kind of low speed differentiator. First we have JFET a peak detector, with low leakage and then a comparator made with an instrumental amplifier (NOT THE EXACT PART IN SCHEMATIC - LT1001->INA 826, AD795 ->TL082).
It works well, but from time to time, the output signal "jumps" lets say a volt.
I've tried almost everything. I think that the issue is related to a bit of charge in the JFET gates due to the high impedance of R2. Do you think that it could be solved changing the JFET amplifiers for bipolar amplifiers?. To my knowledge, they are more immune to electrostatic noise although they have more leakage current (I can assume it). There is something really curious, if I touch the board, it jumps, even if I blow over the board!. Once I saw a signal conditioning circuit for the same sensor made out of bipolar transistors, and it worked smoothly.
Also, if you have any bipolar amplifier suggestion pin compatible with TL082 it would be great.
Any comments or ideas are welcome.
Thanks in advance
I have an issue that is driving me mad and consuming the time my doctor says I should use to exercise...
I use this circuit in an inductive sensor, is a kind of low speed differentiator. First we have JFET a peak detector, with low leakage and then a comparator made with an instrumental amplifier (NOT THE EXACT PART IN SCHEMATIC - LT1001->INA 826, AD795 ->TL082).
It works well, but from time to time, the output signal "jumps" lets say a volt.
I've tried almost everything. I think that the issue is related to a bit of charge in the JFET gates due to the high impedance of R2. Do you think that it could be solved changing the JFET amplifiers for bipolar amplifiers?. To my knowledge, they are more immune to electrostatic noise although they have more leakage current (I can assume it). There is something really curious, if I touch the board, it jumps, even if I blow over the board!. Once I saw a signal conditioning circuit for the same sensor made out of bipolar transistors, and it worked smoothly.
Also, if you have any bipolar amplifier suggestion pin compatible with TL082 it would be great.
Any comments or ideas are welcome.
Thanks in advance