What is this component? - Page 1
Forum section: electronics / beginners

author: BRetonDP
author_rank: Contributor
timestamp: December 21, 2014, 03:53:55 am
content: Hello, fellow EEVB members. Very quick question here!A pal of mine went to a store to ask for a diode (he wanted a rectifier diode, but was new to electronics and had no idea of what they looked like). According to him, this is what he received when he asked for a diode. Can anyone explain to me what this is and what it does? Obiously, the weird thing for me here is the single lead.

author: sleemanj
author_rank: Super Contributor
timestamp: December 21, 2014, 04:01:46 am
content: Stud diode maybe? If so, case will be one 'ode and the pin the other, used for very high current.

author: aveekbh
author_rank: Regular Contributor
timestamp: December 21, 2014, 04:22:20 am
content: Yes, the body is possibly the other terminal. You could check this with a DMM.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 21, 2014, 04:24:09 am
content: Press fit diode. You need an arbor press, a die to push it in (a pipe section, so you don't crush the lead or the encapsulant), and a precision hole in the heatsink.Rather archaic these days, though I think they still turn up in alternators? I don't work with alternators, so I don't know how true that is...Tim

author: theoldwizard1
author_rank: Regular Contributor
timestamp: December 21, 2014, 04:34:49 am
content: Quote from: T3sl4co1l on December 21, 2014, 04:24:09 amEvery alternator has 6 of them !

author: BRetonDP
author_rank: Contributor
timestamp: December 21, 2014, 04:39:58 am
content: I see, I hadn't thought of that. Thank you all for your answers!

author: SeanB
author_rank: Super Contributor
timestamp: December 21, 2014, 06:47:53 am
content: Most alternators these days no longer use them, though you still get them as a common replacement part for 20-30 year old cars. The most common diode block in alternators now is a pair of pressed steel or aluminium plates, with 3 dimples, that have a chip diode stuck down with LMP solder or conductive epoxy, and with a short stiff lead that is welded or soldered to a plastic carrier, with the 3 phase leads in a trio of punched tinned brass strips. The diode is protected with some flexible sealer puddled to fill the dimple.Typically as well 3 of the diodes are zener diodes, with a breakdown voltage of around 35-50V, put there to limit voltage output of the alternator if the regulator fails short circuit, and the alternator charges the battery till it is dry and goes open circuit. Crude, and they will eventually fail short circuit and burn out the alternator safely, ie not much flame and smoke.

author: albert22
author_rank: Regular Contributor
timestamp: December 21, 2014, 04:50:55 pm
content: Alternator diodes. Some types are color coded because the pin could be the anode or the cathode. Car alternator used three of each type. Basically is a three phase rectifier, 3 diodes pressed into a bar connect to ground and 3 diodes pressed into a separate bar becomes the positive supply. That is why you need two pinouts.

author: tautech
author_rank: Super Contributor
timestamp: December 21, 2014, 05:00:07 pm
content: Quote from: albert22 on December 21, 2014, 04:50:55 pm+1Commonly found in old Bosch & Lucas alternators.

author: SteveH
author_rank: Contributor
timestamp: December 23, 2014, 06:48:50 am
content: Still found by the bucket load in welding machines and plasma cutters that are transformer based.

author: Porch
author_rank: Contributor
timestamp: December 23, 2014, 06:58:55 am
content: Sell it to this guy.

author: LeWidget
author_rank: Regular Contributor
timestamp: December 25, 2014, 12:27:16 pm
content: Hey guys,Wondering if anyone could tell me the name of this component. Its a WiFi connector that gets soldered to the pcb (broke off) and has a cable connected to it that runs to the WiFi transmitter(?) in the modem. Not sure of the technical name for it, Im trying to find a replacement (cost).[]http://

author: retrolefty
author_rank: Super Contributor
timestamp: December 25, 2014, 12:47:33 pm
content: QuoteCoax cable/connector assembly.

author: LeWidget
author_rank: Regular Contributor
timestamp: December 25, 2014, 12:51:45 pm
content: Quote from: retrolefty on December 25, 2014, 12:47:33 pmthanks retronow just trying to locate one that has that little cable/wire attached to it. Most of the ones Ive come across seem to just be the connector. :\

author: aveekbh
author_rank: Regular Contributor
timestamp: December 25, 2014, 02:24:08 pm
content: Hello LeWidget,It looks like a U.FL-SMA connecting cable - the U.FL is the tiny bit, and the threaded bit is the SMA connector. The Wikipedia page has couple of good pictures (permalink:https://en.wikipedia.org/w/index.php?title=Hirose_U.FL&oldid=603717819). Look for a small white plastic connector with a gold-plated pin.The connectors are quite fragile, but they are good for a few removals/insertions. I think you might just be able to reconnect the U.FL to the board and connect the SMA side to the antenna. Could you add pictures of the other side of the connector (cable turned upside down from what it is now), and the detail of the SMA part? APs usually have reverse polarity SMA connections, so the Digikey link below may not be the correct adapter.U.FL to SMA (standard polarity) cable adapters:http://www.digikey.com/product-search/en?pv91=597&FV=fff40018%2Cfff8017b&k=cable+assembly&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25U.FL (I think) to SMA reverse polarity:http://www.digikey.com/product-detail/en/JF1R6-CR3-4I/JF1R6-CR3-4I-ND/1090366Hope this helps

author: Fred27
author_rank: Unknown
timestamp: December 25, 2014, 08:50:16 pm
content: You'll find plenty of those U.FL to RP SMA cables on eBay, often described as replacements for contacting to WiFi antennae.

author: LeWidget
author_rank: Regular Contributor
timestamp: December 26, 2014, 02:57:19 pm
content: Thanks Avee,here's a few more pics. It seems the cable attached is hardwired(?) into the gold/brass connector. (or stuck in pretty hard)

author: aveekbh
author_rank: Regular Contributor
timestamp: December 26, 2014, 03:29:22 pm
content: Quote from: LeWidget on December 26, 2014, 02:57:19 pmThe cable is usually crimped on the SMA side (the threaded brass connector, gold plated).QuoteThat's a RP (reverse polarity) connector - you can see the pin.(Edited)Is the cable broken at the U.FL side? If so, go ahead and order one of the same length (or longer).