the voltage difference can only be measured in a high input
range, resulting in a low resolution
A much better way is to use an oscilloscope with a differential
input.
Figure 3.2: Differential input
A differential input is not referenced to ground, but both sides
of the input are ”floating”. It is therefore possible to connect one
side of the input to one point in the circuit and the other side of
the input to the other point in the circuit and measure the voltage
difference directly.
Advantages of a differential input:
•
No risk of creating a short circuit to ground
•
Only one channel is required to measure the signal
•
More accurate measurements, since only one channel intro-
duces a measurement error
•
The CMRR of a differential input is high. If both points have
a relative high voltage, but the voltage difference between the
two points is small, the voltage difference can be measured
in a low input range, resulting in a high resolution
The Handyscope TP450 is galvanically isolated. This means
that there is no electrical connection between the inputs and the
USB connection. It is therefore not possible to damage the con-
nected computer when (accidentally) making a wrong connection.
3.1.1
Differential test lead
The Handyscope TP450 comes with a special differential test lead.
This test lead is specially designed to ensure a good CMRR.
Introduction
7
Summary of Contents for Handyscope TP450
Page 1: ...Handyscope TP450 User manual TiePie engineering ...
Page 4: ...7 11 Measure lead 27 7 12 Package contents 28 II ...
Page 6: ...2 Chapter 1 ...
Page 18: ...14 Chapter 3 ...
Page 24: ...20 Chapter 4 ...
Page 28: ...24 Chapter 6 ...