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| Mastech MS5308 LCR meter with ESR measurement - on discount at the moment |
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| digsys:
Mine should be here any day now - Does it NEED the 12VDC Input? or can we use a 9VDC Plugpack (also popular). If there's series dropping diodes, it'd much easier to bridge them out than adding a regulator? I'd have no problem with that fix. |
| alm:
I think one of the diodes is for reverse polarity protection, and the other is for switching between battery and AC power. I didn't study the circuit in detail. I tested the minimum input voltage, and I think it shut down at somewhere close to 9 V (don't remember if it was below or above it), so I would expect a 9 V wall wart to be too low / unreliable. |
| robrenz:
--- Quote from: kripton2035 on January 17, 2013, 09:33:37 pm ---you need 4 wires probes to make real measurments on an lcr meter --- End quote --- That is what I thought but why does the Agilent U1733C not have 4 wire connections at all? I have asked this in multiple threads but no one ever responds. I am not Agilent bashing! I just dont understand how they can properly do a open/short cal with only 2 leads. |
| PA4TIM:
There are more ways and different modes. With inductors the testlead form an inductance, shorting the leads makes it posible to compensate for that inductance, it also compencates for resistance. But leads akso do have capacitance. An open calibration eleminates that. Looks good. But, the Capacitance changes with position of the wires, the capacitance and inductance are still there. A capactor or inductor under test have paracitics too. So the total is a rather compex network. So to really compensate there must be a lot of complex math going on in the LCR meter. There are 2, 3, 4 and 5 wire ( and i believe even more) measurements. Two wire is good for clipping components dirct to the meter. 3 wire is used on almost all bridges including one of the best C meters ever made. This uses guarding. This takes away the paracitic capacitance of cables and shields them from external signals. But not for the resistance. I'm not sure about selfinuctance. I use my bridges not much for percicion L measurements. I use my vna or a special 2 terminal pH resolution self-inductance bridge for that. If i measure capacitance uing a three wire methode and guarded dutholder on my GR1620 paracitic capacitance is less as 1 pF and D is at zero, after 2 coax cables that are 1 meter long. If i use two wire this way it is around 80 pf. A bridge is ble to measure phase differences so three wires will do. 4 wire is most times for non bridge configurations by sourcing the test current through two wires and measuring the voltage result and phase between voltage and current direct at the DUT. This is the main reason they use it. Testsignal and resultsignsl are separted and so reducing errors. Whit to wire you can not measure phase error and this is the most important thing while trying to split an impedance into a resistive part and reactancet. Shielding or guarding the cables is again possibble to compensate for stray capacitance. But this is a very incompete and rough explanation. There are several general radio experimenters downloadable at IET labs that go in depth about all methods inluding a lot of math. Also the Agilent impedance measurement handbook goes into detail ( and they wrote some articles about measuring very small impedances. This is allways 3 or more wire. There is many literature about this, |
| nixxon:
Important message from seller of my MS5308 that confirms problem with the AC power adapter: From: support2@aidetek.com To: "nixxon" Subject: Very urgent issue regarding power adapter for MS5308FW: Item #380482359785 Date: Fri, 18 Jan 2013 02:53:34 -0800 Very urgently! Thank you very much for your purchase MSTECH MS5308, I am very sorry to let you know the manufacturer found a bug in power adapter for MS5308, so please do NOT use power adapter for MS5308 LCR meter, it may burn your meter, once we have further solution from manufacturer, we will let you know and we sincerely apologize for the inconvenience for you, please feel free to contact us at support@aidetek.com if you have any further concern regarding this, thank you very much for your cooperation. Come back to our ebay stores for more new items: http://stores.ebay.com/smtzone http://stores.ebay.com/AideTech-USA Thanks and best regards, Cherry Tan www.aidetek.com 22 Straton Ct. Parlin, NJ 08859 USA Tel: (408) 329-7985 Fax: (866) 571-5680 e-mail: support@aidetek.com |
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