An High Voltage question of Tektronix THS730A(THS700)

For grounded test equipment, one should use two probes, one for the high side, one for the low side, and measure the difference. In this case, one could use a battery powered DVM (or scope) provided safety precautions are met, the measuring instrument is insulated from ground AND one does not touch the equipment when that power is on (!!!).

Robert Baer wrote in news: snipped-for-privacy@earthlink.net:

The THS700s are battery-powered,insulated scopes. I'd worry about potentials between each probe,though.

I'd worry too.

the Tek 222/222A/222PS had preamps with isolation barrier, seperate for each of the channels. This technique easily allowd 500V diffrence between both channels, and still save work (not too high humidity conditions, of course).

The THS7xx uses a little bit different input technique, so I would not risk going that high.

hth, Andreas

snipped-for-privacy@bigfoot.com (TekMan) wrote in news: snipped-for-privacy@posting.google.com:

Do you know of anyone with component-level schematics of the THS series scopes? I believe they're in the same category as TDS scope;no schematics in the "service" manual.

No Jim, I am sorry: I don't know anyone. seems you are absolutely right with your statement.

But I'll let the newsgroup know if I find schematics - may be someone else who reads this has a contribution/donationof suc hschematics? This would be real nice.

Andreas

Andreas,

Did you mean that the THS700 will be damaged if I don't use TEK's HV probe(P5210) for common-mode voltage larger than 30V? Or it's just a safety consideration for floating voltage?

You have mentioned 160 V and higher in your first posting. See the difference to mentioning now 30V?

well, to my opinion I ALWAYS would use a probe. Depending on the floating voltage you have and the BW you need to measure: chosse the P5210 or a simpler (not-HV) one - that's depending on your measurement setup.

hth, Andreas