Buy inductance meter in USA - Page 1
Forum section: electronics / beginners

author: robsims
author_rank: Frequent Contributor
timestamp: June 10, 2022, 12:12:31 pm
content: Hi, i want to buy a inductance meter or a inductance/capacitance (LC) meter. My budget is around $50. I want to order it from the USA. Anyone know a good inductance meter or Inductance/capacitance meter. Many thanks in advance

author: beanflying
author_rank: Super Contributor
timestamp: June 10, 2022, 12:21:22 pm
content: Given your Budget the little Evilbay LCR meter are actually fairly good within their stated ranges. You also get some Transistor and FET identity capability for a few $. One of those did me really well until I found some money for some decent gear.And the MEGA Thread about themhttps://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 10, 2022, 01:08:27 pm
content: There is not much choice for USD50.The transistor tester already mentioned is a quite useful thing and has an excellent performance for it's price, and because it's such a useful tester for finding pinouts and quick checks whether transistors still work it's good to buy at least one anyway.I wrote at least, because these are already a good buy just if you want to play with an atmega328 and an LCD (you have choices of quite a lot of different LCD variants (character, monochrome or color graphical and different resolutions).Another option is to buy or build one based on an LM311 comparator. I think these are a bit more accurate.If you want a "real" LCR meter, then the DER EE 5000 is an excellent choice. Prices on Ebay start around USD90, but that is without any accessories, and for a meter of this class you really want some accessories with it, but those are relatively expensive Just the TL-21 for example is almost USD40.Some 10 years ago Dave did a teardown of it in #229Almost everything in it is integrated in a single IC and that is why it is relatively cheap for it's quite good performance. I do have some doubt though if the USD 90 variants are real DER-EE-5000 meters or whether they are fake.I really do not understand the market for highly accurate (USD 4000 +) LCR meters, mostly because inductors are not very precise parts and even their inductance changes with frequency.If your main interest is in power inductors for SMPS circuits, then you are best off with a stack of:1. Shunt resistor.2. Power MOSfet with a suitable driver.3. Inductor to test.4. A few electrolytics that can delilver 40A for a bunch of milli seconds.5. Oscilloscope + function generator (to make pulses for the MOSfet driver).With this setup you can calculate the inductance from the di/dt slope on your oscilloscope. It's not very accurate, but you can also see how the inductor behaves when it is saturated. And if you already have an oscilloscope and function generator, it a quite simple and quick build.

author: robsims
author_rank: Frequent Contributor
timestamp: June 10, 2022, 02:05:16 pm
content: Since there is no good meter around the $50 pricepoint I'm going to order the Peak LCR45 meterhttps://www.digikey.com/en/products/detail/peak-electronic-design-limited/LCR45/9687219

author: beanflying
author_rank: Super Contributor
timestamp: June 10, 2022, 02:08:48 pm
content: If you are getting to that price have a look for what you can get the DER 5000 for locally. They are a much better meter.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 10, 2022, 02:45:43 pm
content: Your link to the Peak LCR45 is more expensive then the DER EE 5000.I would not even consider buying that toy myself.What sort of measurements do you want to make with your meter?If budget is really such a constraint, you are probably better off by starting with the transistor tester, and if that is not good enough, it at least buys you some time to save up to get the DER EE 5000.I started some 15+ years ago by building an LM311 based LC meter, because real LCR meters were too expensive for me. This meter worked quite good, but with no other reference, I could only compare it with the values printed on inductors itself, but they always matched close enough, and series connections of inductors also turned out correct. Later I added a few of the "transistor tester" gadgets to my equipment and both meters agree with each other close enough.I was tempted to buy the DER EE 5000 when it became available. It's quite reasonable in price, and performance is comparable with meters twice it's price. I'm not on a tight budget myself, and I could easily buy it now, but the simple fact is that the combination of the homebrew LM311 meter and the transistor tester is simply good enough for my purposes, and that is the only reason I never bought the DER EE 5000 myself.

author: ledtester
author_rank: Super Contributor
timestamp: June 10, 2022, 03:10:45 pm
content: Quote from: Doctorandus_P on June 10, 2022, 01:08:27 pmA site explaining how that LC meter works:https://sites.google.com/site/vk3bhr/home/lcm1Speaking of the LM311-based LC meter... it would be nice to see it incorporated into the TransistorTester.Update: I'm not totally sure, but I think these aliexpress products basically use the LM311 LC meter design: