Products > Test Equipment
AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter
Fungus:
--- Quote from: cjs on July 19, 2017, 02:28:40 am ---My PM-18C has different holes in the amps ranges; instead of 100?A/1000?A/1000mA/10A (.01/.1/1000/100k ?A resolution) it's got 60?A/60mA/600mA/20A (i.e. .01/10/100/1000k ?A resolution). So it drops a bit off the bottom to give a bit more in the middle
--- End quote ---
IIRC there's an expensive Agilent that jumps from 600uA to 6A.
crazyguy:
--- Quote from: matura713 on July 19, 2017, 09:34:57 am ---
i don't think that's an issue (as far as not some external components to DM1106EN are crucial for the resolution), because what to measure on what position depends on the EEPROM settings - the same how C/F temperature measurement are added to mV position on AN8008. basically, you should be able to re-arrange what position measures what just with changing bytes in the EEPROM.
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the measurement function not only depends on the eeprom settings. It also requires external components with proper wiring.
in the DTM0660L reference design, it uses 3 shunt resistors (0.01ohm, 0.99ohm, 99ohm) with a combination of eeprom settings (#1 change the gain of the amplifier; #2 control the decimal place), to cover all the current ranges from 60uA to 20A. (60uA, 600uA, 6mA, 60mA, 600mA, 6A, 20A).
in the AN8008 design, it seems that it only use 2 shut resistors, I would guess you cannot simply change the eeprom settings to achieve your goal.
boggis the cat:
--- Quote from: Fungus on July 19, 2017, 10:30:17 am ---IIRC there's an expensive Agilent that jumps from 600uA to 6A.
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The U1230 series? It is low-end for Keysight (Agilent).
I think this is done as they're using the V terminal, and taking the uA circuitry from there. They can't allow many mA through as this low impedance pathway would then compromise the safety. (And the A path can't deliver accurate mA indications.) You can only get uA 'for free' from the V terminal.
Having separate A and uA/mA terminals resolves this.
stj:
are there any schematics about for 0660 based meters with the NCV function?
i'm curious what components are involved and the only meter i have here is an 8002.
crazyguy:
--- Quote from: stj on July 19, 2017, 03:34:14 pm ---are there any schematics about for 0660 based meters with the NCV function?
i'm curious what components are involved and the only meter i have here is an 8002.
--- End quote ---
NCV measurement schematic
the antenna pickup the AC signal
0 - 50mV, display shows "EF"
50 ~ 100mV, "-" 1 bar
100 ~ 150mV, "- -" 2 bars
150 ~ 200mV, "- - -" 3 bars
> 250mV, "- - - -" 4 bars
the sensitivity can be programmable
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