Agilent 4155B/4156B User’s Guide Vol.2, Edition 5 8-5
If You Have A Problem
When You Make A Measurement
If Measured Value Oscillates when Measuring
High-Frequency Devices
When measuring parameters of high-frequency devices, such as GaAs MESFETs or
high-frequency bipolar transistors, oscillation may cause measurement problems.
Normal measurement cannot be performed because of oscillation.
To solve this problem:
• For FETs, add resistive ferrite beads as close as possible to the gate.
• For bipolar transistors, add resistive ferrite beads as close as possible to the base
or emitter.
• Make connection cables as short as possible. Long wires cause oscillation
because of their large inductance.
Test Device
Ferrite
Beads
To u n i t
To U n i t
UGT06002, 90x40