Elektor ESR / C Meter (September 2005)

[sonytel]

Hello.
1) I am testing the ESR/C meter and detected some inconveniences.
The point +Bat this directly connected one to the feeding of the OP LF412, and is not this tension interrupted by the switch S2. to that this is?
2) when I try to adjust the tension from Offset to 40mv, does this become impossible, does the same one vary since between 30 and 50 mv, is this variation due to that this present the sign of 200Kz? coming from the PIC16F84
3) when I try to measure the ESR of a capacitor, this he/she gives me among 0,7 and does he/she go ascending up to 3, is this normal? since comparing the measures with the Meter ESR published in Elektor 270 of 2002, the measure stays in 0,5 and it doesn't vary.
Then measuring a capacitor with an ESR value of 52 with in ESR to of elektor 270, november 2002, and when measuring it with the ESR/C tester, is the measure of 22, is this undoubtedly lagun problem in the adjustment of the tension of Offset?

Best regards
Gabriel Beguiriztain
Argentina