DM4070 LCR Meter

Hello! Recently I have bought an LCR Meter: DM4070 because usually I need to check the capacitors higher than 20uF. My oldiest multimeter MASTECH M890F has some limits like all, because it mixes more functions. For capacitors it measures between 2000pF to 20uF, so a 22uF I cannot measure.

I had a look on the market and on the Internet and I found dedicated capacimeters, capacimeters+ohmmeters and LCR meter, so I decided to buy an LCR meter for condensers and inductances, because my MASTECH measures resistences up to 200M ohms.

My question is what does it mean that ”5” when it is shown in manual the accuracy, for example between 200pF and up to 200uF the accuracy is +/-(2.5% +5), after 200 up to 2000uF the accuracy is +/- (5%+5)...

I see that that five is also shown for the resistors and inductances.. why? What is in fact the tolerance of the device? Or that 5 is a constant??

Which is better for capacitors and resistors, in precision MASTECT M890F or DM4070?
 

Salas

diyAudio Chief Moderator
Paid Member
2002-10-08 11:31 am
Athens-Greece
It means plus 5 counts for least significant digit. Its overall accuracy is as in quoted % PLUS last digit unreliable up to number +/-5. That means you better measure at most digits after the dot available range for a given signal or parameter so the uncertainty is least. edit: M890F does not state count because probably worse. Basically at base prices you don't get a truly accurate meter for matching components reliably under true 1%. Best handheld LCR is the IET D-5000 in my opinion.
 
So, if I understood good, the accuracy and also the tolerance is +/-2.0 + the 5 ureadable digits (if there are). The tolerance is +/-2.0. So if I measure 24pf on 200pf scale I can read the best result and if I measure 24pf on 2000pf (2nF) the accuracy is lower, not so clear, right? From your point of view, this is a good accuracy for the instrument DM4070?
 
The M890F has an auto-adjust for starting in every case from 0 for the capacitors, voltage, ampers, frequency and hFe and only for resistors it starts from 1. ___

DM4070 has a fine knob trimer or pot which adjust for 0. The 0 modifies if I move from 200p to 2nF or 20nF. After 20nF is insignificant its adjustment..

M890F has also dot. But it is different the scale 2000pf (without dot)from the M890F to the 2nf (with dot and adjustment)from the DM4070. After you, it is better for capacitors the DM rather M890F?? I see that DM goes more precise or more easy stabilies than M890F which is a little unstable because for capacitors usually tries to find the smaller/upper value if I let a capacitor in it.. This fact depends most or almost for the quality of capacitors: I saw if there is a ceramic one..hardly arrives to a given value and has a big tolerance; if there is a multistrat more easy arrives to the value and if is a polyester or stiroflex when you insert it that value is! there are very precise and stable, from my point of view.
 
I have M890F since 2004 or 2005. I trusted in it. I see minor - maybe differences at caps.. Let.s say a 68nF on Mastech is 71,2nF and on DM is 69,4nF.. A 1,8nF marked on Mastech is 1860pF on 2000 scale or 1,85 on 20nF scale and on DM is 1,779. Why and where is the difference? Also at 100nF on Mastech is 101nF and on DM 99 there are.......

the measurements were made without wires..caps on sokets.
 

Salas

diyAudio Chief Moderator
Paid Member
2002-10-08 11:31 am
Athens-Greece
Because you can trust DM4070 better by spec and it gives you higher uF to recognize bigger capacitors also. The example 1779pF for 1.8nF is probably not 1860pF or 1.85nF is more dependable. Being an LCR it can also tell you about inductors which the other one being a DMM can't. The main criterion is what you need it for. If you don't match components down to 2.5%, if you don't test inductors for diy loudspeakers, if you don't check electrolytics up to 2000uF too often, then there is no reason not to only use the Mastech DMM for everything you do.
 

hutale

Member
2014-10-07 9:30 pm
meter kit that measures

This kit does not measure, it just displaying values.
The measuring belongs to instruments which are accepted for a calibration certificate by the calibration labs.

It is easy for me to ignore this topic and not spoil the fun of people who dream a large hamburger that cost just 5 cent of a dollar.
But as long I am living in real world, is my duty to inform and protect others in a consumer level.
Most non-certified products are worthless designs and waste of cash.