Hello,
I’ve been looking for a scope. A few of the scopes that I see mentioned a lot, Siglent, Rigol etc., have a max input voltage of 300V. If that’s the case, how would I measure power supplies in a lot of tube gear since it’s is common to have voltages much higher than that?
Thank you
I’ve been looking for a scope. A few of the scopes that I see mentioned a lot, Siglent, Rigol etc., have a max input voltage of 300V. If that’s the case, how would I measure power supplies in a lot of tube gear since it’s is common to have voltages much higher than that?
Thank you
Depends on the type of measurement. If it's noise, you'd use an RC high pass with the capacitor blocking the DC. If it's turn-on / turn-off behavior, you'd use a voltage divider.
Since you're clearly a DIY engineer, this should be easy to implement. Consider voltage, power dissipation, bandwidth, probe loading, etc.
You can always just buy a "high voltage / 100X probe" for it. We used to use the Tektronix P5201 - you can get one on ebay for $250 at the moment - better than <10X the "new" cost. That's 25 MHz bandwidth - there's probably others to buy not quite as fancy.
My Fluke 123 scope can go well over 1200VDC - but it's a dog to use compared to the bench style scopes. I keep it because it can do certain measurements other scopes would need expensive "accessories" to be able to do. They're fairly cheap on ebay -
Since you're clearly a DIY engineer, this should be easy to implement. Consider voltage, power dissipation, bandwidth, probe loading, etc.
You can always just buy a "high voltage / 100X probe" for it. We used to use the Tektronix P5201 - you can get one on ebay for $250 at the moment - better than <10X the "new" cost. That's 25 MHz bandwidth - there's probably others to buy not quite as fancy.
My Fluke 123 scope can go well over 1200VDC - but it's a dog to use compared to the bench style scopes. I keep it because it can do certain measurements other scopes would need expensive "accessories" to be able to do. They're fairly cheap on ebay -
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Thanks,
Agreed on the Fluke 123. I have one and it can be a pain. It works fine but has some a few vertical and horizontal deal pixel lines. Fluke wants $700 for a new screen so I figured I’d just replace the whole scope.
Agreed on the Fluke 123. I have one and it can be a pain. It works fine but has some a few vertical and horizontal deal pixel lines. Fluke wants $700 for a new screen so I figured I’d just replace the whole scope.
A reputable 100x probe is how you do it, but some cheaper scopes don't have an option to specify x100 so you'll have to do the division in your head...
A dodgy unbranded 100x probe could be junk and blow up your 'scope's frontend when it flashes-over internally...
Don't make the mistake of adding an attenuator on the output of a 10x probe either, its not
designed for high voltage.
A dodgy unbranded 100x probe could be junk and blow up your 'scope's frontend when it flashes-over internally...
Don't make the mistake of adding an attenuator on the output of a 10x probe either, its not
designed for high voltage.