Tektronix Oscilloscope Probe Readout Pin? What is if for?

[gmcjetpilot]

I have a Tektronix 2235A Oscilloscope that came with P6109 150KHz probes.
Tektronix probes have that ground pin at the collar of the BNC.
My generic China made X1/X10 probes that I had before don't have the ground pin.

There is no automatic switching from X1/X10 range, the selector dial for Vert
Deviation has both scales, you just look at the right scale on the knobs dial scale.

It seems in X10 the China probe reads less than the Tektronix?

Any detailed info would be great.

 

[IRstuff]

Theere is something at the end of the probe that identifies a Tektronix-compatible probe to the oscilloscope as a 10x or 1x probe, so that the oscillscope will automatically adjust the display to the correct scale.

TTFN

FAQ731-376

 

[gmcjetpilot]

Thanks. SO with the Tektronix scope I have, it does nothing since there is no automatic switching. However it does give
different X10 results from the cheap China made X10 probe. Either that probe is off or that readout pin does something else. I was thinking it's a resistor to ground and does some compensation? The China probe must be off? Other wise I wounder if they did it just to make their probes proprietary?

 

[IRstuff]

I don't recall ever having a problem with non-Tek probes, but it's been a while since I've used one...

It's most likely that the cheap probes are just cheap...

TTFN

FAQ731-376

 

[ScottyUK]

Does that scope have an on-screen cursor? The probe will automatically re-scale the Y cursor to give a true readout. At least, that is what it does on the 24xx series scopes.


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If we learn from our mistakes I'm getting a great education!

 

[gmcjetpilot]

No the 22XX series don't have any on screen cursors or data. They are basic scopes. The confusion was that the
Generic probes are reading different in X10. I did some
more A B comparison and the Tek Probe is fine and the
China made probe is reading low in X10. It has nothing
to do with the read pin (I think). The Generic China
probe is OK in 1X.

 

[IRstuff]

So, maybe a bad switch...

TTFN

FAQ731-376

 

[gmcjetpilot]

I found the PROBLEM with the low reading Generic China made probe. With help of the Tektronix Yahoo group, I checked the celebration. I did calibrate the generic China probe on the new scope, BUT I had the switch in X1 not X10. I recalibrate it the probe with the switch in X10. It is fine now. X1 Cal is still fine also? I'll BE HONEST, I did not know that made a difference or at least think about it. I lost the Cal instructions long ago. Any way Cal those probes boys and girls. And if it has a switch Cal it in X10 and check X1 as well.

 

[VEBill]

I find it amusing that the Chinese made o'scope probes are about $6, including world-wide shipping. It's very revealing.

 

[itsmoked]

Yeah. It shows that in this screwed up world the price of things has nothing to do with their cost.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

About calibration: You do not need to calibrate x1. The reason is that since there is no series resistor, there is no parallel capacitor, and hence no need (or possibility) to calibrate it. So, calibrating x10 is fine. Nothing more needs to be done.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[gmcjetpilot]

"Skogsgurra (Electrical) 24 Oct 10 16:04 WROTE:
About calibration: You do not need to calibrate x1. The reason is that since there is no series resistor, there is no parallel capacitor, and hence no need (or possibility) to calibrate it. So, calibrating x10 is fine. Nothing more needs to be done."

From some movie, "I KNOW THAT NOW!" Ha ha. Yep that makes sense. It was just a switch error; I should have calibrated it in 10X, my mistake. Thanks for pointing out 1X is straight through nothing else. Cheers!