Chapter 4 Features and Functions

HP 34902A 16-Channel Multiplexer

HP 34902A 16-Channel Multiplexer

This module is divided into two banks of eight channels each. All 16 channels switch both HI and LO inputs, thus providing fully isolated inputs to the internal DMM or an external instrument. When making 4-wire resistance measurements, the instrument automatically pairs

channel with channel to provide the source and sense connections. The module has a built-in isothermal block to minimize errors due to thermal gradients when measuring thermocouples.

 

Backplane Switches

Channel Switches

Internal

 

 

DMM Input

98

 

 

 

 

 

100Ω

 

 

100Ω

Reference

 

Bank Switch

Junction

99

Sensor

 

100Ω

 

 

100Ω

Internal

 

 

DMM Input

 

 

(4W Sense)

97

 

NOTES:

01

08

Com

Com (4W Sense)

09

16

If any channels are configured to be part of the scan list, you cannot close multiple channels; closing one channel will open the previously closed channel.

Current measurements on this module will require external shunt resistors.

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HP 34970A manual HP 34902A 16-Channel Multiplexer