{"id":2150,"date":"2014-12-10T15:13:23","date_gmt":"2014-12-10T23:13:23","guid":{"rendered":"http:\/\/pididu.com\/wordpress\/?p=2150"},"modified":"2015-04-04T21:23:47","modified_gmt":"2015-04-05T05:23:47","slug":"dm4070-lcr-meter-review","status":"publish","type":"post","link":"http:\/\/pididu.com\/wordpress\/blog\/dm4070-lcr-meter-review\/","title":{"rendered":"DM4070 LCR Meter Review"},"content":{"rendered":"

I have a need to measure home-wound inductors in the range of 10 – 100 \u03bcH (It’s for the power transfer controller of the solar bicycle<\/a>). <\/p>\n

On eBay, I found quite a few “universal” 12864 testers based on the atmega328 for as low as $13. Those would measure L, C, R, as well as semiconductors. However, I could find no spec in the descriptions for the inductance measurement range. The image here<\/a> suggests that the maximum resolution is 0.01 mH (10 \u03bcH) – not really good enough if I want to distinguish between, say 13 \u03bcH and 18 \u03bcH.<\/p>\n

My final choice was the DM4070. At $31.50 (US seller, free shipping), it was the cheapest LCR meter that would do what I needed.<\/p>\n

\"flat-rate<\/a>
The DM4070 arrived in a flat-rate envelope.<\/figcaption><\/figure>\n
\"generic<\/a>
The box is generic, showing some other models perhaps that leverage the same case. Who cares, I’m probably going to recycle the box, anyway.<\/figcaption><\/figure>\n
\"box<\/a>
The box contained the meter, a set of short alligator clip test leads, and a poorly-written manual.<\/figcaption><\/figure>\n

Included with the meter was a poorly-written manual<\/a>. Perhaps it was translated from Chinese? The translation was intelligible, as long as I used imagination.<\/p>\n

\"torn<\/a>
Although there was no shipping damage to the unit, one of the insulating boots on a test clip was torn. It’s still functional.<\/figcaption><\/figure>\n
\"plastic<\/a>
There is a plastic stand that swivels out on the back to hold the meter at an angle. The plastic was so flimsy, and so difficult to pull out, that I was afraid I was opening it the wrong way.<\/figcaption><\/figure>\n

After the quick visual examination of the unit, I pressed the power button. Nothing.<\/em> Maybe batteries weren’t included? I slipped off the shock case, removed a philips screw, and looked into the battery compartment.<\/p>\n

\"battery<\/a>
Not good. I also cleaned up the tiny bit of corrosion on the case screw, for good measure.<\/figcaption><\/figure>\n
\"dead<\/a>
Confirmed, the included battery is dead.<\/figcaption><\/figure>\n

I put a fresh 9-volt battery in, and the DM4070 powered up fine. Fortunately, none of the chemical leakage from the battery appeared to have gotten into the actual device. I’m wondering: does the DM4070 go through batteries quickly? It’s supposed to automatically sleep after being idle for a few minutes, but I haven’t personally witnessed this behavior, yet. I’ve been turning the meter off after every use.<\/p>\n

My first measurement was of a known inductor. I first shorted the test leads together to determine the lead inductance. Actually, the operation manual says not to do this, but I think that warning was intended for capacitance measurements, or perhaps to save power.<\/p>\n

\"lead<\/a>
Before doing a low inductance measurement, I shorted the leads to see what their inductance would be.<\/figcaption><\/figure>\n
\"HL-KK110U\/BC<\/a>
After accounting for lead inductance of 1.4 \u03bcH, the measurement of this HL-KK110U\/BC 10 \u03bcH inductor was spot-on.<\/figcaption><\/figure>\n
\"transformer<\/a>
The 220-volt primary of this torroidial transformer was over 12 Henries.<\/figcaption><\/figure>\n

Next, I measured some capacitors. I tried a few and found the measurements to be mostly good. Possibly the measurements of high value capacitors were a little low. The DM4070 reported my 1000 \u03bcF capacitor as being 953 \u03bcF. I might have chalked that up to component tolerance, except that I had measured that lot of capacitors previously with my a test jig of my own design, and believed that they were more like 1100 \u03bcF.<\/p>\n

\"cap<\/a>
There’s a trim knob to null out test lead capacitance. It only<\/em> applies to capacitance, however. For inductance and resistance, the user must mentally compensate.<\/figcaption><\/figure>\n
\"loose<\/a>
There are integrated slots which are supposed to accept direct insertion of components. The clips are too narrow to take a wire larger than about 16 gauge, yet too loose to hold most component leads firmly. Shown above is a 470 pF capacitor reading as 0.6 pF, until I jiggled it to make contact. It’s usable, but if there was one change I could make on this meter, it would be to substitute a higher quality clip.<\/figcaption><\/figure>\n

Finally, I measured some resistors. The readings were quite accurate, except on the 20 M\u03a9 range, where they seemed to read 5% high. Some of it might have been component tolerance. Actually, I’m pleased to have a 20 M\u03a9 range at all – cheap digital voltmeters often top out at 2000 k\u03a9 (2 M\u03a9). The 2 M\u03a9 range is actually missing on this meter, so if you need to measure things in the hundreds of k\u03a9 with precision, this is not the meter for you.<\/p>\n

One thing that I noticed is that on the high value ranges, the readings took a few seconds to settle to a final value. This is fine, as long as one knows to wait.<\/p>\n

Here are the test results:<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Component<\/th>\nLabeled<\/th>\nReading<\/th>\nNotes<\/th>\n<\/tr>\n<\/thead>\n
Inductor<\/td>\n10 \u03bcH -0+30%<\/td>\n9.6 \u03bcH<\/td>\nAfter subtracting 1.4 \u03bcH for leads<\/td>\n<\/tr>\n
Inductor<\/td>\n30 \u03bcH -0+30%<\/td>\n29.7 \u03bcH<\/td>\nAfter subtracting 1.4 \u03bcH for leads<\/td>\n<\/tr>\n
8.5V winding<\/td>\n<\/td>\n43.9 mH<\/td>\ntorroidial transformer secondary<\/td>\n<\/tr>\n
14.9V winding<\/td>\n<\/td>\n150.7 mH<\/td>\ntorroidial transformer secondary<\/td>\n<\/tr>\n
115V winding<\/td>\n<\/td>\n3.27 H<\/td>\ntorroidial transformer primary<\/td>\n<\/tr>\n
105V winding<\/td>\n<\/td>\n2.59 H<\/td>\ntorroidial transformer primary<\/td>\n<\/tr>\n
220V winding<\/td>\n<\/td>\n12.35 H<\/td>\nabove 2 windings in series<\/td>\n<\/tr>\n
Capacitor<\/td>\n75 pF<\/td>\n77.3 pF<\/td>\n<\/td>\n<\/tr>\n
Capacitor<\/td>\n470 pF 5% C0G<\/td>\n.477 nF<\/td>\nceramic<\/td>\n<\/tr>\n
Capacitor<\/td>\n2700 pF 5%<\/td>\n2.73 nF<\/td>\npolystyrene<\/td>\n<\/tr>\n
Capacitor<\/td>\n1 \u03bcF<\/td>\n1.001 \u03bcF<\/td>\nceramic<\/td>\n<\/tr>\n
Capacitor<\/td>\n4.7 \u03bcF<\/td>\n5.05 \u03bcF<\/td>\nsolid tantalum<\/td>\n<\/tr>\n
Capacitor<\/td>\n100 \u03bcF<\/td>\n96.3 \u03bcF<\/td>\naluminum electrolytic<\/td>\n<\/tr>\n
Capacitor<\/td>\n470 \u03bcF<\/td>\n457 \u03bcF<\/td>\naluminum electrolytic<\/td>\n<\/tr>\n
Capacitor<\/td>\n1000 \u03bcF<\/td>\n953 \u03bcF<\/td>\naluminum electrolytic<\/td>\n<\/tr>\n
Resistor<\/td>\n0.62\u00a0\u03a9 1%<\/td>\n0.62\u00a0\u03a9<\/td>\nAfter subtracting 0.08 \u03a9 for leads<\/td>\n<\/tr>\n
Resistor<\/td>\n11\u00a0\u03a9 5%<\/td>\n11.37\u00a0\u03a9<\/td>\nAfter subtracting 0.08 \u03a9 for leads<\/td>\n<\/tr>\n
Resistor<\/td>\n137\u00a0\u03a9 1%<\/td>\n136.9\u00a0\u03a9<\/td>\n<\/td>\n<\/tr>\n
Resistor<\/td>\n562\u00a0\u03a9 1%<\/td>\n.561 k\u03a9<\/td>\n<\/td>\n<\/tr>\n
Resistor<\/td>\n16.2 k\u03a9 1%<\/td>\n16.18 k\u03a9<\/td>\n<\/td>\n<\/tr>\n
Resistor<\/td>\n33 k\u03a9 5%<\/td>\n33.1 k\u03a9<\/td>\n<\/td>\n<\/tr>\n
Resistor<\/td>\n180 k\u03a9 5%<\/td>\n.19 M\u03a9<\/td>\n<\/td>\n<\/tr>\n
Resistor<\/td>\n2.2 M\u03a9 5%<\/td>\n2.36 M\u03a9<\/td>\n<\/td>\n<\/tr>\n
Resistor<\/td>\n3.3 M\u03a9 5%<\/td>\n3.43 M\u03a9<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

I have a need to measure home-wound inductors in the range of 10 – 100 \u03bcH (It’s for the power transfer controller of the solar bicycle). On eBay, I found quite a few “universal” 12864 testers based on the atmega328 for as low as $13. Those would measure L, C, R, as well as semiconductors. … Continue reading DM4070 LCR Meter Review<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[66],"tags":[65,157,158,159,82,221],"_links":{"self":[{"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/posts\/2150"}],"collection":[{"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/comments?post=2150"}],"version-history":[{"count":0,"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/posts\/2150\/revisions"}],"wp:attachment":[{"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/media?parent=2150"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/categories?post=2150"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/wp-json\/wp\/v2\/tags?post=2150"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}