HV probe

I tried to download the P6015A manual. I was already logged into the Tek site, but it made me fill out a full ID form anyhow. Then their download script crashed. I filled out a contact form, requesting the manual, and now I'm getting emails from sales people about products and promotions. No manual.

Tektronix is crap now, products and people. My DPO2024 is awful and buggy, and they don't care. It's made in China, and I suspect they have no access to the programmers to fix the bugs. If you're going to buy a Chinese oscilloscope, it may as well be Rigol.

John Larkin is crap now, and always has been.

So, when I say crap, you claim I have a fetish, but when you say it it is okie dokie, eh?

You're one of the biggest hypocrites in this group, if not the biggest.

You sit at the very bottom of that totem pole.

P6015A manual -

P6015 manual -

The P6015 is filled with a very small amount of Refrigerant 114 (mostly in the gas state). The P6015A is filled with high voltage silicon oil.

You cannot use R11 in place of the F114 in the 6015 probe.

An axial-lead 1G resistor (I have some around) would make a fine DVM multiplier.

It would be very slow into a scope. Probably.

Actually, it overshoots a lot, and the amount depends on local shielding. Not a good scope probe.

But you can use FC-40 Fluorinert. It develops nearly no head pressure at all..

Because the can said so (to 1985, at least). R-11 (Trichlorofluoromethane) was common in HV power supplies for electron microscopes and xray systems as well - boils at about room temperature. R-114 (1,2-Dichlorotetrafluoroethane) is similar but with a lower boiling point and was sometimes used to provide positive pressure to exclude water and with a sealed system is considered nearly interchangeable for HV purposes.

Both are chemically inert and, likely, would fall under the Fluorinert banner if they were sold by 3M instead of Dupont.

If you check the Tek website for the current version of the probe, you should notice that "silicone oil" is now being used.

Pressure has nothing to do with it.

As long as you don't mind exploding scope probes.

Try butane!

The most important factor is the dialectric property of the gas. R-114 is very near 1.0. The probe may be compensated with just air but at a lower voltage. If you use something else, you won't be able to get the 75 MHz bandwidth.

Well, a miniature one could be the core of an alternate DC-DC supply. The earliest development TVs did this; then, fairly early on, they combined HV with sweep, which is convenient. It's resonant, so it's low noise, relatively speaking. (Considerably later, when multisync monitors came out, they split things up again; but my Trinitron has a HV MOSFET driving its FBT, so it's pretty conventional, not more than quasi-resonant I would imagine.)

Not that a pair of high Q coils, where two frequencies and a coupling have to be precisely adjusted, would be all that handy for production. :)

Applications of interest to me include RF and "switching" amps made with tubes. Not many "applications", of course, but those simply aren't things I can poke at with a regular 400V probe. (I know: I already tried a long time ago. That's why my Tek 475 has some replacement resistors shoved into one of its vertical attenuator blocks!)

Tim

There is a compensation adjustment on the probe, several in fact, that will make up for tiny changes in the Er of the gas.

The gas is mainly an insulator. Most gasses have Er on the order of

Pressure has EVERYTHING to do with it. You obviously did not read the manuals you posted links to.

Tektronix specifically states that the use of a different fluid could cause too much pressure in the vessel and cause it to burst. THAT is a DIRECT function of vapor pressure, which varies with temperature, and especially so with refrigerants or fluorocarbon fluids.

Nice try though.

Wrong. It is about the reluctance to arcing. Some are fully filled with fluid and have no gas at all.

We are talking about the P6015.

Er of R-11 is near 2.

The compensation in the probe itself is some metal plates forming a capacitance to the HV resistor. Matching to the scope is done in the module that connects to the scope.

I have some of the R-114 and both probes. It really is an amazing probe when you think about it.

In liquid phase. I thought the old (pre-silicone) probe was filled mostly with gas.

Like most scope probes, the compensation trim at the BNC end makes the C ratio match the R ratio, at which point the step response is flat.

sage

sure

When I was at the FEL, there was a some big waveguide that lead from the klystron to the accelerator sections, over pressured with SF_6 to reduce breakdowns... or something.

George H.

SF_6 is also used in X ray machines for the same reason.

Dan