Tektronix TDS210 oscilloscope inside photos

[AndrejaKo]

Hi guys!

A friend of mine has a TDS210 and is thinking about connecting it using good quality 1000x probes to a 600 V thermionic valve circuit. How safe would that be? Also if I'm hijacking the thread too much, please tell me.

[echen1024]

Uh... hang on, where are the relays to switch stuff in that board, like AC, DC and Gnd coupling, attenuation? Are they just doing what autoranging handheld multimeters do to attenuate the input? The analog frontend doesn't look like a frontend at all. There seems to be too little stuff in there. That means it should be interesting to see how they do it in an schematic.

Tek could make a handheld scope out of the chips used in here (using updated versions, and some intput protection of course).

There is one optomos in that input stage. the rest is voltage divider with fet switches.

Why isn't this used in other oscilloscopes like the DS1052E and the Agilent rebadged Rigols (I assume they are the same)? It sounds cheaper and the bandwidth of those scopes is the same as these.

I think Tek patented their electronically switched attenuator scheme (designed by John Addis).  Maybe it hasn't expired yet.

Huh. I should just go buy one and turn it into the 'open hardware oscilloscope,' and add in a good multimeters. It would be a win-win!

[alm]

A friend of mine has a TDS210 and is thinking about connecting it using good quality 1000x probes to a 600 V thermionic valve circuit. How safe would that be? Also if I'm hijacking the thread too much, please tell me.

As long as the valve circuit is floating or grounded, this should be fine. The ground clip of a 1000x probe is still directly connected to ground. Even a good 100x probe should be sufficient, assuming it's 600 VDC or low frequency AC. 600 V RF is a totally different ball game. Note that the bandwidth of the HV probes designed to multimeters is quite limited (maybe a kHz or so). If it's a real scope HV probe (eg. Tek P6013/6015/6015a), then it will have decent bandwidth.

Be careful with AC coupling, though. The maximum voltage in AC coupling mode is determined by the scope, and this is likely less than 600 V (check the manual).

[AndrejaKo]

Thanks! The frequencies will be pretty low, since it's an audio amplifier.