Table 4. The voltage ratio between the air core sensor and ferromagnetic core sensors without the attenuation resistor
Frequency (Hz)
V
Rod
/ V
Air
ratio
V
Stack
/ V
Air
ratio
V
Roll
/ V
Air
ratio
10
661
749
235
100
159
186
59
1,000
154
237
63
10,000
7
7
7
40,000
2
1
2