Agilent Technologies 46A, 45A, 54835A manual To test input resistance

Chapter 3: Testing Performance

To test input resistance

To test input resistance

This test checks the input resistance of the vertical inputs. A four-wire measurement is used to accurately measure the 50-Ωand 1-MΩinputs.

Specification: 1 MΩ ±1% and 50 Ω ±1.5%

Equipment Required

Equipment	Critical Specifications	Recommended Model/Part
Digital Multimeter	Measure resistance (4-wire) at better than	Agilent 34401A
	0.25% accuracy
Cables (2)	BNC	Agilent 10503A
Adapter	BNC Tee (m)(f)(f)	Agilent 1250-0781
Adapters (2)	BNC (f) to dual banana (m)	Agilent 1251-2277

Procedure

1Set up the multimeter to make a four-wire resistance measurement.

2 Assemble the test cables.

aUse the two BNC-to-banana adapters to connect one end of each BNC cable to the four- wire resistance connections on the multimeter.

bConnect the free ends of the cables to the BNC tee. See figure 3-3.

Figure 3-3

To ohmmeter 4-wire inputs

To oscilloscope channel input

Input Resistance Equipment Setup

3Connect the male end of the BNC tee to the channel 1 input of the oscilloscope.

4 Press Default Setup to set the oscilloscope to default conditions.

5Press the Input key for Channel 1 to select 1 MΩ, then 50Ω, and verify resistance readings of 1 MΩ ±10 kΩ and 50 Ω ±0.75 Ω respectively.

6Record the readings in the Performance Test Record.

7 Repeat steps 3 through 6 on the remaining channels.

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