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Attenuators in series?
Attenuators in series?
Can I place two attentuators in series to increase the measurement range of voltage? For example, can I plug one TA197 10:1 attenuator into a second TA197 to achieve a 100:1 ratio?
Thanks in advance!
Thanks in advance!
Re: Attenuators in series?
In theory yes, but in practice it will really depend upon what you are trying to achieve by doing this. What do you need to measure ?
Martyn
Technical Support Manager
Technical Support Manager
Re: Attenuators in series?
I'm thinking of using a second Attenuator in series to test a source for which I'm uncertain of the max voltage. I could start by simply measuring voltage on an ordinary DMM, but the DMM won't be fast enough to pickup momentary spikes.
I would only use the second Attenuator in series for an initial test until I am confident about the max voltage. Then I will remove it, assuming I'm within the margin of safety.
In the scenario where I leave it in because it's needed, would you happen to know if there is more noise from two 10X Attenuators in series vs. one 100X Attenuator?
I would only use the second Attenuator in series for an initial test until I am confident about the max voltage. Then I will remove it, assuming I'm within the margin of safety.
In the scenario where I leave it in because it's needed, would you happen to know if there is more noise from two 10X Attenuators in series vs. one 100X Attenuator?
Re: Attenuators in series?
What is the source of the voltage, and what scope are you using?
Martyn
Technical Support Manager
Technical Support Manager
Re: Attenuators in series?
You should not try to cascade two TA197 10:1 attenuators for 2 reasons. The first is safety - the attenuator is rated at 400V max. Using 2 in series does not increase the safe working voltage - it is still 400V.
The second reason is that you will not get the right attenuation - the TA197 is designed to be plugged into an oscilloscope with 1M ohm input impedance. If you use 2 in series the one plugged into the oscilloscope will provide 10:1 attenuation but the one plugged into the first attenuator will not. The input impedance of the attenuator is 8 M ohm so it will attenuate by around 2 not 10.
If you need to measure a signal that is >400V then I suggest you use a differential scope probe designed for high voltage work https://www.picoauto.com/products/electric-and-hybrid-vehicle
The second reason is that you will not get the right attenuation - the TA197 is designed to be plugged into an oscilloscope with 1M ohm input impedance. If you use 2 in series the one plugged into the oscilloscope will provide 10:1 attenuation but the one plugged into the first attenuator will not. The input impedance of the attenuator is 8 M ohm so it will attenuate by around 2 not 10.
If you need to measure a signal that is >400V then I suggest you use a differential scope probe designed for high voltage work https://www.picoauto.com/products/electric-and-hybrid-vehicle
Re: Attenuators in series?
I have the Picoscope 2205A, rated at 20V.
I understand your explanation, and this Q&A was a good learning opportunity. Thanks
I understand your explanation, and this Q&A was a good learning opportunity. Thanks
Re: Attenuators in series?
Please do not go out and buy a x100 attenuator for the purpose without fully understanding what you are intending to measure, and the safe practices for doing it.
If you describe in detail what you are trying to do then we can give further advice.
If you describe in detail what you are trying to do then we can give further advice.
Martyn
Technical Support Manager
Technical Support Manager