What are the most common useful inductor values? - Page 1
Forum section: electronics / beginners

author: Dan123456
author_rank: Regular Contributor
timestamp: October 10, 2023, 11:53:01 am
content: I was just about to put an order through for some components but found the total was a little under what I had budgetedSo, as always in these situations, I started browsing and one thing I came across that I do not really have in my stockpile is inductors.So my question is, what are the top ~5-10 most common inductor values you would recommend stocking up on / are always worth having on hand?Alternative, feel free to say “Na, save your money for more IC’s!” if you think specific inductors should really be bought for specific jobs

author: JohanH
author_rank: Frequent Contributor
timestamp: October 10, 2023, 12:01:55 pm
content: This is only a hobby for me and I don't stock inductors. They have so different use cases so I've usually ordered a specific inductor for a specific application. If you are into RF stuff, maybe you could have the small axial inductors and/or the similar SMD types in stock. My two € cents.

author: wraper
author_rank: Unknown
timestamp: October 10, 2023, 12:07:15 pm
content: You don't want to stock them unless have specific tasks. It's very specific what inductance and current ratings you need, and dimensions if it's for repairs. For some general noise filtering you may have some ferrite beads, value not critical.

author: wraper
author_rank: Unknown
timestamp: October 10, 2023, 12:12:47 pm
content: And you don't want to have much of IC's either. Maybe various vreg/LDO, a few opamp types, a few logic, but that's about it. Having a lot of that garbage I find detrimental to dig through parts because I remember I should have something. Would be faster to just order. Also you tend designing around what you have instead of what's the best for the task. The only things that are really worth to keep in stock are resistor and capacitor assortments.

author: RAPo
author_rank: Super Contributor
timestamp: October 10, 2023, 12:36:41 pm
content: Take a look at thefrom EEEEA bit expensive but I find them very useful.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 10, 2023, 12:39:05 pm
content: Same as the kits of values for resistors and capacitors, there are kits of inductors.However, it is not that easy to make a "top ten most popular inductors". Inductors vary wildly in mechanical size and in construction, depending on the application where the inductor is used.Order the needed value or fabricate them on the spot, only for the specific project you are working at, not in advance.For example, I have collections of most values for resistors and capacitors, and they've been very useful to be at hand in the lab. Not so much for inductors. Ordered once a kit of small values (looking like 0.25W resistors), but almost never used any of the inductors.What I did use quite often, is recovered coils and recovered magnetic cores from scrapped electronic boards. I also keep various diameters of copper wire, for just in case I need to hand made small coils on the spot.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 10, 2023, 12:43:25 pm
content: It all depends on what sort of things you do. Do you build small SMPS circuits for uC's or do you build loudspeaker filters? There is such a wide variety in use of inductors that it is hard to give some "general guidelines".In my own experience uC's are quite susceptible for EMI though all connected wires (Especially when working on matrix board for one-off projects), and in such cases some kind of inductor is always needed to make it work reliable (instead of just on your test bench). Common mode filters are good to have some (with different current ratings), and I think the inductors with a straight ferrite rod and one layer of turns on them are best for EMI suppression because of the low capacitive coupling between input and output.If you just want to do some experiments with inductors, you can salvage some from old PCB's or buy an assortment kit or two (one with the "resistor size" inductors (small current, but quite cheap) and some for higher currents (either toroidal or the square SMT type).Despite the extremely wide assortment of inductors, they are made with an surprising low spread of their values. Resistors and capacitors can be bought easily with a spread of about 12 orders of magnitude, but for inductors it's much less.But why buy extra inductors? Have a look at other things around you. I recently added a "busboard" brand breadboard to an order out of curiosity. and now I'm thinking of throwing away all my old board breadboads and buying more busboards because of the quality difference. When working with breadboards, it's also nice to have a bunch of single row headers (both male and female) and matrix board (for making simple / weird adapters). I also find the splitable ferrite cores handy for ad-hoc EMI trouble shooting. You can easily clamp them on a power cable to see if that helps to prevent your uC resetting when you switch that CFL light.I never like regular probes for DMM's. Instead I use two strand "speaker wire" (despite it's stiff insulation), put banana jacks on one end and the very small Hirschman 2mm plugs on the other end. I have drilled coaxial holes in the connectors and soldered tips of needles in them. I can easily stick these pins in a breadboard, poke them though insulation, or clamp them in between strands of multi strand wire, and because of their small size the do not fall off so easily. I have also clamped a bit of bicycle inner tube in between my DMM and it's rubber holster, and use that flap to "store" some 2mm crocodile clamps so they are always with my DMM.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 10, 2023, 12:48:06 pm
content: If, by value, you mean "inductance", very few component types are shopped "by values", but inductors the least. Real inductors are far from ideal components (defined only by inductance), and instead have bunch of complex data instead of just inductance value, so that you pick a suitable part number (not inductance value) for each application. Inductors are almost exclusively used for power conversion (switch mode converters) and power filtration. In both cases, parameters like core loss (AC loss), DC resistance, saturation current and thermal current rating are important, so for a given converter, out of the 100 000 inductors on market maybe only 10 are suitable, even if 1000 are of correct inductance value.Resistors are probably the only passive components you want to stock in significant range of resistance values.

author: CaptDon
author_rank: Super Contributor
timestamp: October 10, 2023, 01:02:46 pm
content: With audio it doesn't make sense to stock anything as they will be big and heavy for the most part. Also, audio frequency inductors tend to be used as power supply ripple filtering chokes and mostly with tube circuits. With R.F. I have many in stock for experimenting and I find them at ham radio flea markets (hamfests). The old 1mH, 1.5mH and 2.5mH chokes are handy and I have several 'tunable' inductors of various types. Old dinosaur hams like me always had/have a stockpile of 'AirDux' open wound coils with polystyrene supports. There are several makers, Miller, Millen and Barker & Williamson and there are charts on how to cut or tap them for the inductance and power you desire. Hams used these from 1.8MHz up to at least the 144MHz band and they made bandswitching coils up to 1KW. All of that said, it isn't practical to stock a lot of different values and the values you want to have on hand for experimenting is based more on what frequency or band of frequencies you experiment with.

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 10, 2023, 01:18:44 pm
content: Just like resistors or capacitors, it's not just the raw value, there're other important parameters, the saturation current is very important when choosing and inductor.2.2u / 10u / 22u / 47u are commonly seen in switching regulators, but unless you're designing one, it's very unlikely you'll ever replace any, they're robust and rarely fail.Then there're those power filtering chokes, usually rated at 1K @ 100MHz which also rarely fail unless you mishandle the board.Better buy a bunch of electrolytics, smd resistors or whatever, inductors are among the rarest elements that need repairing!

author: tszaboo
author_rank: Super Contributor
timestamp: October 10, 2023, 02:10:42 pm
content: 1-15nH 0402 RF types. Because I only need to solder them myself when doing RF matching.

author: Dan123456
author_rank: Regular Contributor
timestamp: October 10, 2023, 04:20:03 pm
content: Awesome! Thanks allI had heard that the 3 important / common passive components were resistors, capacitors and inductors so figured people must stock up on a few really common ones like we do for the other 2 categoriesSound like that is not the case at all!Thanks allQuote from: wraper on October 10, 2023, 12:12:47 pmCompletely agree mate! My IC stockpile mainly consists of 555’s, one IC type of each of the different gates (AND, OR, etc.), counters (probably not strictly necessary… I just really like the 4017 for some reason), optocouplers and voltage regsI do have a bunch of more specialised IC’s like audio amps, op amps, microcontroller’s etc. in smaller quantities but found even with just a reasonable sized stockpile I have had to start keeping a list as have already somehow ended up with like 3 different BCD to 7 segment IC’s

author: RoGeorge
author_rank: Super Contributor
timestamp: October 10, 2023, 05:13:22 pm
content: Quote from: Dan123456 on October 10, 2023, 04:20:03 pmJust as a fun aspect, R, C and L are "predicted" by Maxwell's equations. However, there are 4 equations and only 3 components, why so?Well, there is a 4'th fundamental electrical component, known but not really.Not kidding, it's called thememristor.

author: CaptDon
author_rank: Super Contributor
timestamp: October 10, 2023, 05:15:52 pm
content: I don't mind a large stock pile of I.C.'s dating from the very old to the very new. I have them sorted in a sensible manner 7400-7420 / 7421-7440 etc. and like wise with the CMOS and linear stuff. In this age of computerized spreadsheets I have an accurate inventory. I am always open to donations of parts from friends 'cleaning house' or companies throwing away everything that dimwits (I mean six-sigma assholes) tell them to. Case in point. One place where I formerly worked hired Cornell students to come in and tell us what to dispose of. We paid $50,000 for this service!!!! We tossed about $100,000 of inventory 'To save space and taxes on old stock'. Then within about a 2 year period we paid out around $50,000 to either re-stock the items that were deemed useless but yet used a few times each year or to have custom manufactured replacement parts hand made for our machine room floor as we had thrown away our spare parts!!! I rescued a bunch of brand new Watlow F4 PID loop controllers still in the box from the dumpster and sent them to one of our other divisions. At that point in time with the options we ordered they were about $1000.00 each!!!I have friends and even business associates that call me for obsolete I.C.'s for their equipment repair needs!! I have indeed been treated to some nice lunches or suppers for supplying an oddball I.C. here and there!