TDS 1002 to read high voltage

Hello,

Anybody know if it is possible to read 5000v pulses on a digital scope, the TDS 1002 from Tektronic. I have this unit, taking the voltage from a 12v car battery and supposedly giving off pulses of 5000v to 6000v. I want to see what kind of pulses. If it is possible , how do I go about it.?? I did test the device and i did not see anything on the scope, then i found out my probe was deffective by using a second probe and testing that probe on a battery. Did it break my probe or was it coincidence.

thanks,

ken

Reply to
lerameur
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By the way, I was putting my multimeter to the device (and set to Ac voltage) and it was reading 270v. The probe i use (P2220) can take up to 300v.

ken

Reply to
lerameur

"lerameur"

** Buy 10 x 2kV ceramic caps of 100pF each - wire them all in a series string and put that inside a plastic tube.

Connect a 10 nF cap ( say 500 V) across the tip and ground of your scope probe.

Connect the string of caps between the source of pulses and the probe tip.

Ground the scope to the common of the pulse source.

You have just made a 1000:1 capacitive divider probe.

The input load is only 10pF.

6 kV pulses will show as 6 volts ones on the scope.

......... Phil

Reply to
Phil Allison

Ken,

If you we using a standard X1 or X10 probe, you may have damaged it. Fortunately, it appears your scope input was robust enough to not be damaged, though you may have to fully test it (all voltage ranges and various frequencies). You could purchase a X100 probe. Check with you favorite supplier.

Good luck, Richard

Reply to
Richard Seriani

He is talking about short duration pulses.I am not sure exactly how short the duration is ,but if the input source is a car battery,its got to be very short duration indeed. In such a case,the parasitic resistance of the 10 100pf capacitors might prevent the final capcitor from charging fully. So a better idea may be to use a voltage divider that divides the voltage in a 1:100 ratio(say 10ohm and 10Kohm).it would do exactly the same thing as the above,but has 2 advantages

1)requires only 2 components to do the same job 2)this scheme would work even if the pulses have very short duration BUT make sure that the resistors you use can dissipate enough heat(i.e they are big enough) as the peak current of the ciruit would be about 0.5 to 0.6 amps.
Reply to
anirudh

"anirudh the dangerous fool"

** Complete DRIVEL !!!!!!!!!!

** Absolute BOLLOCKS !!
** It won't work at all, you pig ignorant moron.
** Will drastically load down the 6 kV pulse generator and totally *f*ck* the measurement.

Plus 10 kohm resistors that can stand repeated 6 kV pulses are LARGE expensive & not readily available.

Unlike 100pF, 2 kV ceramics.

...... Phil

Reply to
Phil Allison

first of all,i've got to thank you.I learnt a lot by reseaching this stuff after your colorful reply :)

So far as i know ,resistors DO NOT have a maximum voltage rating.They ONLY have a MAXIMUM POWER rating. For a given value of current ,the maximum voltage is given by (Power Rating/Current) Therefore you can have a large maximum voltage(for a given power dissipation) simply by decreasing I appropriately. If a voltage divider is used with R1=10Mohm and R2=100Kohm ,then the ratio of voltages is 1000:1. the current is approximately V/(total Resistance)=(5000V)/ (10.1Mohm)=0.5ma(approx)

A current of 0.5 milliamperes is unlikely to do that,though a current of 0.5 amps might.The resistance values are therefore to be incresed.In this respect you were right. The power dissipated is VxI=5000x0.0005=2.5W resistors with 2.5 watt power dissipation are not rare.

Capacitors DO have parasitic resistances.And they DO take time to charge and discharge,unlike resistors which respond to voltage changes instantaneously.Therefore for signals lasting for very short durations ,capacitors are not the ideal solution .Because of this parasitic resistance there will always be a time delay between the output and input of a capacitor network,which becomes significant for input signals of very short duration. And this is not "bollocks".It is basic circuit theory.

as shown above,it can very well work,after increasing the values of the resistors appropriately.

I never said that you were wrong. I merely said there was another way of doing things,which might be better in this situation.

Reply to
anirudh

i just did a google search on the address from which this guy phil has been posting from.i discovered that pretty much all his posts on forums were full of obscenities and mindless criticisms of other people.his google account seems to have been banned for the same reason in retrospect i feel really sorry at losing my cool.sorry if i offended any well-meaning folk. but the reference to my professor ,and the derogatory reference to hinduism was the last straw.henceforth i shall just ignore this guy.

Reply to
anirudh

Yeah, but he knows his stuff, and is rarely wrong.

--

Bye.
   Jasen
Reply to
Jasen Betts

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