Measurement Tutorial
The HP 34401A is capable of making highly accurate measurements.
In order to achieve the greatest accuracy, you must take the necessary
steps to eliminate potential measurement errors. This chapter describes
common errors found in measurements and gives suggestions to help
you avoid these errors.
Thermal
EMF
Errors
Thermoelectric voltages are the most common source of error in
low-level dc voltage measurements. Thermoelectric voltages are
generated when you make circuit connections using dissimilar metals
at different temperatures. Each metal-to-metal junction forms a
thermocouple
, which generates a voltage proportional to the junction
temperature. You should take the necessary precautions to minimize
thermocouple voltages and temperature variations in low-level voltage
measurements. The best connections are formed using copper-to-copper
crimped connections. The table below shows common thermoelectric
voltages for connections between dissimilar metals.
Copper-to-
Copper
Gold
Silver
Brass
Beryllium Copper
Aluminum
Kovar or Alloy 42
Silicon
Copper-Oxide
Cadmium-Tin Solder
Tin-Lead Solder
Approx.
m
V / °C
<0.3
0.5
0.5
3
5
5
40
500
1000
0.2
5
The HP 34401A’s input terminals are copper alloy.
198
Summary of Contents for 34401A
Page 12: ...1 Quick Start 1 ...
Page 26: ...2 Front Panel Menu Operation 2 ...
Page 50: ...3 Features and Functions 3 ...
Page 103: ...4 Remote Interface Reference 4 ...
Page 135: ...SCPI Status System 4 Chapter 4 Remote Interface Reference The SCPI Status Model 135 ...
Page 170: ...5 Error Messages 5 ...
Page 182: ...6 Application Programs 6 ...
Page 196: ...7 Measurement Tutorial 7 ...
Page 214: ...8 Specifications 8 ...