In most electronics repair forums, when the young ones realizing that capacitors damage is at the Top of the list as cause that a motherboard or a TFT monitor or TV set stops working , they do get exited about to become doctors by them self’s.
Equivalent Series Resistance three words translated to ESR.
Their next move is to start a hunt on eBay, so to discover the necessary ESR meter which it would become their capacitors diagnostic tool.
Those people by realizing that everything comes for a price they start to get attracted by all sort of gismos named as ESR meter.
But their major problem is that they do not know of what they need exactly as technical features, and which one to trust?
This post is going to be a reply to all those confused souls.
As first I will say that capacitors are not growing on trees, they are manufactured items and their manufacturing and testing is made by tremendously expensive tools and all process occupying too an enormous amount of electronic engineers which are also testing and verifying the ultimate quality of these electronic components, before they got shipped to the world.
In order to keep things simple to understand, I will say that ESR is just one of the parameters that maters, measuring capacitance and testing frequency are also extremely important.
The testing frequency for its capacitor it is suggested by it manufacturer, and especially the Low-ESR capacitors are measured in Milli-ohm.
1000 Milli-ohm is equal to 1 Ohm.
The value of 22 Milli ohm could be the starting point as ESR (internal resistance) of the new high quality Low-ESR capacitors, and it would look over the LCD display of a LCR meter or ESR meter as 0.022 and therefore if your gadget does not have the necessary display resolution of four digits? Then it is crippled and a poor design.
Most trained professionals are also aware that accurate measurements in the range of Milli-ohm it can be performed only by tools supporting four wires measurement which also have the necessary test leads.
Regarding test frequency as I have all ready mentioned, it is dictated by the manufacturer of the capacitor.
And it could be in the range of 100Hz or up to 100 KHz, now when the manufacturer sharing the capacitor technical specifications by their data-sheets, all measurements can be verified only if the test instrument comes with the necessary technology so to perform this test.
Unfortunately, not even one up to date, from the named as ESR meters are capable to perform an 100% reliable measurement of a Low-ESR capacitor.
Their product designers of such things, are mostly amateurs in programing of such devices, and do not use any high precision electronic parts when assembling their gadgets.
Handheld meters which can do such measurements reliably are few and they are named as LCR Bridge.
Among their advantages is that by a single measurement they offer information about four parameters which are necessary for a complete capacitor evaluation.
Today I got lucky by finding one 10 Milli-ohm SMD resistor over the PCB of a Li-Ion charging controller which was inside in the battery pack of my ACER laptop.
By this resistor I am now able to test the self calibration and the test leads of my DE-5000 LCR meter prior making any very Low-ESR measurements.
Self calibration for LCR meters equals to relative mode of multimeter, it is performed by the user as many times is needed, but the LCR meter it does store the fine adjustment caused by the calibration in it memory, and using it at the next power up.
In summary with out a true reliable meter at hand you are not even capable to verify if your newly purchased Low-ESR capacitors are fakes or not.
In the end of the day the stubborn one will say to him self that…. I am not that demanding … so the cheap meter is OK for me.
And my last respond to him will be that … the one who does repairs that bring food on his table, he better follow the path of wisdom.
Topic: Why cheap ESR meters are worthless? (Read 9754 times)
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