Electronics > Beginners
Why are scope probes so damn big?
Mechatrommer:
there are currently one tested as working, the other is unknown...
https://www.ebay.com/itm/Tektronix-P6563A-500-MHz-20X-4-7-pF-9-5-Mohm-1-3-m-L-SMD-Probe-Tested/222626935327?hash=item33d599721f:g:J7oAAOSw9h9ZpE-l:rk:3:pf:0
if you are in US you maybe lucky, the shipping to my place is 3X the probe price.
the as is one...
https://www.ebay.com.my/itm/Tektronix-P6562A-350-Mhz-Probe-REF/263671436305?hash=item3d640ad411:g:XMMAAOSw-YZa8iGm:rk:2:pf:0
https://www.ebay.com/itm/Tek-Tektronix-Voltage-Probes-Lot-P6136-P6106A-P3010-P6131-P6111B-P6109B/263859240666?hash=item3d6f3c7eda:g:mSgAAOSwISNbjcYD:rk:8:pf:0
new...
https://www.ebay.com.my/itm/Tektronix-P6562A-350-MHz-SMD-Probe-Cable-New/322198362153?hash=item4b0484d829:g:mz0AAOSwo4pYZhGQ:rk:1:pf:0
premium used (with case)...
https://www.ebay.com/itm/Tektronix-P6563A-set-SMD-Probes/232466955873?hash=item36201c3e61:g:YMgAAOSwAwRZo5jg:rk:1:pf:0
(those links will only valid from few months to few years or days so better quick than sorry)
David Hess:
There is a very specific and stupid reason for this.
A couple decades ago, UL and the other regulatory agencies got involved and forced the creepage and clearance rules to be applied to test instrument probes and connectors. The result was all of the standard subminiature 400 volt oscilloscope probes being removed from the market and multimeters and other test instruments losing their more convenient binding posts for guarded connectors.
The exact date can be tracked down by looking through the old Tektronix catalogs to find exactly when the standard subminiature probes were removed.
KE5FX:
--- Quote from: David Hess on November 11, 2018, 11:06:57 pm ---There is a very specific and stupid reason for this.
A couple decades ago, UL and the other regulatory agencies got involved and forced the creepage and clearance rules to be applied to test instrument probes and connectors. The result was all of the standard subminiature 400 volt oscilloscope probes being removed from the market and multimeters and other test instruments losing their more convenient binding posts for guarded connectors.
The exact date can be tracked down by looking through the old Tektronix catalogs to find exactly when the standard subminiature probes were removed.
--- End quote ---
Eh, I don't know if I buy that. Why not just keep selling the same probes, but re-rate them for 48V max?
Wolfgang:
First, "normal" probes are made to be held by human hands and this means that they have a size where is is easy.
If you need it very small probes making reliable contacts with alligator clips and tips comes to a limit when you think of 0.2mm spaced FPGA pins or the like.
Keysight and others have made very small probes that can be soldered into a circuit to keep stray capacitances and lead inductance to a minimum for hight frequency measurements. They cost a fortune, however, and the soldering part needs a microscope.
What you can do is homebrew a small FET probe that can be soldered into a circuit, like here:
https://electronicprojectsforfun.wordpress.com/rf-measurement-techniques/high-frequency-probes/
David Hess:
--- Quote from: KE5FX on November 11, 2018, 11:29:55 pm ---
--- Quote from: David Hess on November 11, 2018, 11:06:57 pm ---There is a very specific and stupid reason for this.
A couple decades ago, UL and the other regulatory agencies got involved and forced the creepage and clearance rules to be applied to test instrument probes and connectors. The result was all of the standard subminiature 400 volt oscilloscope probes being removed from the market and multimeters and other test instruments losing their more convenient binding posts for guarded connectors.
The exact date can be tracked down by looking through the old Tektronix catalogs to find exactly when the standard subminiature probes were removed.
--- End quote ---
Eh, I don't know if I buy that. Why not just keep selling the same probes, but re-rate them for 48V max?
--- End quote ---
The story came from a guy who worked at Tektronix when the new rules came down and they had to sacrifice their existing subminiature probe lines. I confirmed it later by finding the change in their catalogs and like I said, multimeters were also affected, no more binding posts.
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