AD2 scope display

[wanders]

I'm trying to display the output of a 100 watt (30 vrms) audio amplifier. On 1X attenuation, with the range at the max of 5V, the scope will display a complete sine wave up to about 15 vrms;  after that the display exceeds the screen limits. Moving to 10X, the max range is increased to 50V, but the displayed output increases from 15 vrms to 150 vrms: Catch 22. Obviously, I want to decrease the measured output from 15 vrms to 1.5 vrms so that the entire wave will be visible.

[attila]

Hi @wanders

At you using 10x probe?

[wanders]

Thanks for the reply. I'm using the BNC attachment. I send a wavegen signal to the amp; the amp output is sent through a dummy load to the Channel 1 BNC input and displayed on the scope. As noted, the full sine wave display at 30 vrms exceeds the upper limit of the scope. I am trying to find the way to display the full signal on the screen. I think the normal process is to increase or decrease the signal so that it is displayed as 10% of actual value on the screen. Consequently, my use of the Channel 1 attenuation option.

[attila]

Hi @wanders

It looks like you are exceeding the 50V pk2pk range.
The oscilloscope input impedance is 1M Ohm. The 10x probe consist of a 9M series resistor and trimmer for compensation adjustment.
https://en.wikipedia.org/wiki/Test_probe#Passive_probes
https://www.electronics-notes.com/articles/test-methods/oscilloscope/scope-probes.php

You could try:
- to reduce the Wavegen amplitude so the amp output fits in the 50V range
- use 10x probe
- use a 1M series resistor to create a 2x probe

Make sure to adjust the probes:

[Fabio FZ]

On 8/20/2020 at 11:16 AM, attila said:

Hi @wanders

It looks like you are exceeding the 50V pk2pk range.
The oscilloscope input impedance is 1M Ohm. The 10x probe consist of a 9M series resistor and trimmer for compensation adjustment.
https://en.wikipedia.org/wiki/Test_probe#Passive_probes
https://www.electronics-notes.com/articles/test-methods/oscilloscope/scope-probes.php

You could try:
- to reduce the Wavegen amplitude so the amp output fits in the 50V range
- use 10x probe
- use a 1M series resistor to create a 2x probe

Make sure to adjust the probes:

Hi Attila,  I am bulding my own differential probe, so should I use 2 x 9M resistor ( one one on the + and one on the -  input ) for a 10X ? I also need a 100X,  that would ment a 99M resistor ? - a difficult value and I guess that such high impedance I may get into problems. On this case would be better to use a voltage divider ?

[attila]

Hi @Fabio FZ

https://www.google.com/search?q=100x+oscilloscope+probe+diy ?