Agilent Technologies N1022A Podręcznik Użytkownika Pobierz pdf (Strona 35)

Probing 2

N2822/4A Probe Heads

N2820/1A User’s Guide 35

N2822/4A Probe Heads

The N2822/4A heads include an R

SENSE

resistor. Because the

oscilloscope recognizes when these probes are connected, the

oscilloscope automatically knows the value of the R

SENSE

resistor when calculating measurements.

CAUTION The maximum sensor resistor power rating is 500 mW. The maximum

acceptable average current for the N2822A is 5 A

rms

and N2824A is

2.2 A

rms

Burden Voltage When an N2822/4A head is used, the resistance of the

head’s connectors, sensor leads, and internal R

SENSE

resistor

is connected in series with the DUT’s circuit and current is

flowing through the probe head, as shown in Figure 16 on

page 36. Therefore, a burden voltage (I

R) is introduced into

your circuit. Burden voltages may affect the circuit and will

tend to increase the noise. Burden voltages do not affect the

measurement. Table 4 on page 36 lists the resistances added

by various probing components.

NOTE N2825A heads do not contribute a burden voltage as the current is not

flowing through the head.

Tab le 3 Description of Heads

Description N2822A N2824A

SENSE

Resistor 20 mΩ 100 mΩ

SENSE

Tol eran c e ±1% ±1%

Maximum Power Dissipation

500 mW 500 mW

Current Range 250µAto5A 50µAto2.2A

Added Benefit Smaller voltage drop (lower burden voltage). For higher sensitivity (ie. lower noise).

a Temperature coefficient is 20 ppm / °C

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Agilent Technologies N1022A Podręcznik Użytkownika Strona 35