Specifications

2-15
Figure 2-12. Guarding techniques
2.4.8 Grounded device measurement capability
Grounded devices such as the input/output of an amplifier can be measured directly using the I-V
measurement method or the reflection coefficient measurement method (Figure 2-13 (a).) However,
it is difficult for an auto-balancing bridge to measure low-grounded devices because the measure-
ment signal current bypasses the ammeter (Figure 2-13 (b).) Measurement is possible only when the
chassis ground is isolated from the DUT’s ground. (Note: The 4294A used with the Agilent 42941A
impedance probe kit or the Agilent 42942A terminal adapter will result in grounded measurements.)
Figure 2-13. Low-grounded device measurement