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Inductor coils? Answered

How would one go about determining the milihenries value of an inductor coil pulled from an amplifier, well different ones I have found. And living up to it's standards, google has found me no information but what an inductor coil is and it's function, but no information on how to find inductance rating.


Is it physically damaged, like run in with a naughty wire cutter coming to collect money and it refused to pay up, so leg got cut off here and there ?? It's rare to damage them and if it's the inductor I'm thinking it is ?? it's on the output side and you could just by pass it with a jumper wire if it is broke... (( got pic of it ?? ))

I cut them off right at the solder joints, I know I probably should have unsoldered it, but unfortunately my 30W soldering pencil sucks. Picture above.


Is this off a 12 Volt amp ?? because that looks like a switched mode transformer is more then likely is very amplifier specific and altering them will have huge effects on an amp, it controls the input voltage, output voltage and some also set the oscillation of the whole circuit... So I would only use the one for your amp and it's not common for them to fail and if they do your almost better to rewind it exactly like it was wound (( They can be pain to buy )) If your having a problem soldering or de-soldering them try using a propane torch with a small flame and keep it moving around all the pins so you don't burn the board, and hold the PCB upside down and it should just drop out when ready.......

>Is this off a 12 Volt amp ?? because that looks like a switched mode transformer is more then likely is very amplifier specific and altering them will have huge effects on an amp, it controls the input voltage, output voltage and some also set the oscillation of the whole circuit... . Yea it's off a dead car amplifier I was given, I'm not really looking to fix the amp itself, but was rather looking to see if it was the right kind of coil to connect in line with my subwoofer to a normal 2 channel stereo I have here for short term fix until I get a new amp for the sub. I just need a crossover point of around 30-40hz

Oh yeah, forgot you can make notes on the pics in a reply. You'll see there that theres a pair of two strands in the first picture, they wrap around a few times and in the other pictures you'll see the single pair of wires that are seperate, they seem to wrap around a few more times but it's very difficult to tell because the separate strands overlap each other's paths so I can't even count it.

well, you can get multimeter that measures inductance

or if you hav ean ociliscope, you can go to this website

oh, if you just need an inductor, for a project, here is a link for FREE samples, be sure to keep in mind that they WILL call you

ooo a free sample site? Awesome, I'd be up for calling them myself if it'll be free. I don't have an oscilloscope so that's out of the question, however that would most likely probably be my best bet.

Have you readthis instructable? Integrated Circuits are the easiest to obtain, because no one calls you. I have this many ICs _ _


Try ordering a set of nice snap in caps from Panasonic if you want them to call and then visit .... (( and this idea of a rep coming to visit scares the hell out of most but don't worry the rep will load you down with all sorts of good stuff you need but really will play with, I got blue LED's a remote controlled relay board a bunch of other caps a few LCD, some switches a few feet of heavy duty heatsink )) And a good tip is don't put on a tie and try to look all business like, most electronic design engineers wear jeans and t shirt and some even live in there mother's basement ... and show them what your building this is how you find out that most companies sample items that complement your design, I got the heat sink because the rep said the one I have chosen wasn't good enough so he had to do better, wish I knew this before I bought that one ..... They even called the factory paid engineers who did the math to back up there claims .... I just give you the heads up of who I know will call so you know either your willing to deal with a rep or if you just want to buy it ...

I'm under-aged at 14, so, um ya, i won't pass off as an engineer

lol but you have to look 30+ and look like you've had a collage education

So you have to live in your mothers basement, and wear jeans and a tee shirt... <>

Exactly! Not shaving for a couple of days is required too.

If you are seriously building some thing you'd be surprised, A. it's a tax write off for the company providing them, so really it doesn't cost them anything, it's just that much less they have to give the government, B. They tend to view this as a future investment, they have sampled pieces to my kids your age, Ok I know them but still one day you very well could be putting out a design that might sell a few hundred thousand items and you'll use there parts, and this cost them what ?? or right you just saved them that much in there tax payment... But you would have to be serious about building some thing , and whats the worst they'll do ?? Say no, so what have you lost other then a bit of time, and if you build some thing later in life, you'll remember who said no to you..... (( payback sucks ))

I didn't think about it as being a tax right-off i probably will not design a consumer product, but who knows...

Hmm... Well I pulled one coil out of a dead car amp, but for some reason, just like my other dead car amp (no they were given to me dead, wasn't me this time), they both have one torroidal coil, around 2-3 inches in diameter, but with 4 leads soldered on two sides. I pulled one out because I had read that using an air core inductor will give you a certain high freq cutoff freq when used inline with your speaker, seeing the punch bass switch on the side, I figured that each coil was for each setting on the switch (0db, +6db, and 12+db) and that perhaps certain leads had longer windings. Having singled them out, I came out with a clear coated and a red lead as a pair (single strands) and the other two were two strands of clear coated wire and two of the red coating which were both combined together respectivly in pairs of two, so having that, I decided apon using the double pairs, one pair for positive, and one for negative. I literally just plugged it into the speaker jacks on the back of my stereo, and wound the sub wires around the other ends coming out (yes, I burned the coating off for good conduction). It doesn't really sound any different, a lot of the high freq sounds are still coming through, although they seem a little quieter, is there a certain way they need to be wired in combination? I also know that having a second "set" of wires on the same coil induces a current apon said wires from the active wires due to the ferromagnetic properties of the core, which according to wiki, do bounce or 'reverberate' back to the initial live wires, however I doubt that'll do anything but cause minor distortion.. So my annoyingly long question comes out as this, do I need to wire all the strands in a certain fashion or is there something I'm missing here? The coil came out of what I presume was already a subwoofer car amp, so as to why they wouldn't filter out the high freq spectrum like I expected is beyond me..

. Unless you have plenty of spare amps laying around (or plenty of money to buy replacements), you don't need to be screwing around with coils and caps on the output side until you get a better idea of how high-power amps/speakers work. . There are plenty of web pages that explain it. Reading them will save you a lot of burnt up parts.

I understand how it works, everything, probably more than most on this site. However I was looking to find a specific value of mH that I already had calculated off a calculator I found just for it online, I want a value of 36.38mH in order to obtain a 35hz crossover cutoff. As far as conductor coils, there actually is little information as to what they do or how to connect them properly, there is one site that gives some good information, and the calculator is located there.

I'm still wondering though how to properly connect this damn thing.