Keysight 34450A Guia Del Usuario página 98

3 Measurement Tutorial
Noise Caused by Magnetic Loops
If you are making measurements near magnetic fields, take caution to avoid
inducing voltages in the measurement connections. You should be especially
careful when working near conductors carrying large currents. Use twisted-pair
connections to the multimeter to reduce the noise pickup loop area, or dress the
test leads as close together as possible. Loose or vibrating test leads will also
induce error voltages. Tie down test leads securely when operating near magnetic
fields. Whenever possible, utilize magnetic shielding materials or increase the
distance from magnetic sources.
Noise Caused by Ground Loops
When measuring voltages in circuits where the multimeter and the
device-under-test are both referenced to a common earth ground, a ground loop
is formed. As shown in
two ground reference points (V
measurement leads. This causes noise and offset voltage (usually power-line
related), which are added to the measured voltage.
98
Figure 3-2 on page 99, any voltage difference between the
) causes a current to flow through the
ground
Keysight 34450A User's Guide