"Old" electronic components - Page 1
Forum section: electronics / general

author: aaron.soles
author_rank: Newbie
timestamp: November 24, 2019, 07:39:13 pm
content: Ok so I am fairly new here and I don't know a lot of history with various manufacturers. I recently had an opportunity to purchase some new old stock of mainly resistors(primarily Dale). These look to be +/- 1% military spec resistors in various values. I would say there is probably around 1000 pieces give or take, I didn't count along with other various used components, much of which would be a gamble to use(not a big deal for tinkering around). Some of the series numbers include: RN65D, RNR55C, RNR60C, etc. Some of the RNR series appear to be brass or gold?? plated, I couldn't find much info on the plating other than tin coated copper.I guess I would like to know if this would be something worth purchasing and if so how much would be reasonable? Any advice or comments would be greatly appreciated.Thank you,Aaron

author: edavid
author_rank: Super Contributor
timestamp: November 24, 2019, 07:53:04 pm
content: They are 1% metal film resistors, which used to be expensive and exotic, but are now common and worth only 1-2c each.Whether they are worth buying depends on whether they are values you might use, and whether they are sorted by value or in one big bag.

author: Brumby
author_rank: Unknown
timestamp: November 24, 2019, 10:18:39 pm
content: You need to be careful in how you spend your money, otherwise you will end up with mountains of components that you"might use one day"- but find buried in the garage 20 years later under the spare bicycle wheel and broken impact printer.... but, then, it does seem to be one of the rites of passage.

author: aaron.soles
author_rank: Newbie
timestamp: November 24, 2019, 10:48:12 pm
content: Thank you both for the reply's!! I am more leaning toward buying basic component kits to get me started. I think I would rather spend that money on equipment such as a scope, power supply, multimeter, etc. Actually the first project I want to build is a bench power supply, I know everyone does that. I think it will be a good experience to get my feet wet.

author: james_s
author_rank: Super Contributor
timestamp: November 24, 2019, 10:51:25 pm
content: Buy parts that you need, don't just buy random parts, you'll end up accumulating extra stuff anyway. When it comes to resistors I usually buy 100 of any value that I'm buying for a specific project and then ultimately I end up with stuff I tend to use. If you buy kits of stuff or random assortments you end up with a ton of odd value parts likely to just take up space.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 24, 2019, 11:04:53 pm
content: Some of this depends on your style and situation. If you are the kind that wakes up in the middle of the night and wants to try an idea right now a stockpile makes lots of sense. Or if you live in a place which has no local suppliers and online ordering is slow it might also make sense. But if you live in an efficiency apartment, don't waste the space on a stockpile.The parts you looked at are probably fine. It is hard to find values that can't be made to work, and the price should be right (less than or equal to Alibaba or other on line source you have access to).

author: digsys
author_rank: Unknown
timestamp: November 24, 2019, 11:19:20 pm
content: Over the last few years, I've given away / e-wasted several CARLoads of components (used to be a manufacturer). Hardy anyone wanted them any more.Unless you seriously think you'll use SOME of them in a project, I wouldn't even think of it. I still often have to buy old parts, but they are so easy and cheap to pick up.Like others have said - you'll just end up with accumulated piles of dead stock wondering what to do with it :-)

author: james_s
author_rank: Super Contributor
timestamp: November 25, 2019, 12:23:29 am
content: Having a stock of common values is handy, having thousands of one specific value is rarely useful. Some parts I use quite a few of, a friend gave me a thousand or so diodes years ago and I've been using them in projects ever since. I was also given a whole pile of 1k resistors, that's a common value and I've used quite a few of those. Generally I find little reason to have more than 100 of any given part.

author: GlennSprigg
author_rank: Super Contributor
timestamp: November 25, 2019, 12:10:00 pm
content: Quote from: Brumby on November 24, 2019, 10:18:39 pmHaha... You seem to be speaking from experience!!

author: Brumby
author_rank: Unknown
timestamp: November 25, 2019, 12:34:45 pm
content: Guilty - but look around. I'm not alone.

author: jetsam
author_rank: Newbie
timestamp: November 25, 2019, 12:57:38 pm
content: I'd buy them if they were cheap enough and local, especially if I could chat with whoever is selling them about resistors and electronics in general...I buy assortments, some cheap, some not so cheap (Digilent has a nice analog parts kit that has all name brand parts with datasheets available. Ti cloned this kit with digilent later with a "my ti" kit. Lots of op-amps, everything else in modest quantities.) Probably 80% of my stock parts are generic Chinese components including (gasp!) electrolytic capacitors. They're fine for prototyping. If they blow up, you've learned something. They won't, though, in my experience, if you plug them in the right way 'round.I've been filling out with salvaged components recently. It's fun to salvage, and not a trivial task with some things like chokes and transformers, digital interconnects....Building a stash is part of the hobby. I'm aiming for an eventual usage-in-anger rate (i.e. soldered into a permanent project) of 5 percent, and that will be plenty hard to achieve. You're supposed to have more than you use: that's why it's called an inventory or a store of parts, depending on who holds the keys to the cabinet...cheers,jetsam

author: james_s
author_rank: Super Contributor
timestamp: November 25, 2019, 08:54:18 pm
content: I've always salvaged parts but these days I only salvage interesting parts that I can see myself using. I don't bother with resistors unless they're power resistors, and I rarely bother with jellybean parts that I can buy new for under a dollar. I do keep a couple boxes of scrap boards around which I can pull parts from in a pinch though. A specific resistor may cost only a penny but that's no help if it's 10pm and you need one now.

author: aaron.soles
author_rank: Newbie
timestamp: November 25, 2019, 10:48:14 pm
content: Thank You to everyone that replied!! I really appreciate everyone's opinion and advice given! So my 9yr old has been showing some interest in the subject and last year we bought him the elenco snap set. He has completed most all of the basic, non programing stuff and seems to want more. My only gripe about this set is if a component goes bad than it is harder to replace as opposed to a bread board situation. Has anyone had experience with the Make: Electronics book with component kit? I am considering getting this for both him and myself to learn with.

author: Zero999
author_rank: Super Contributor
timestamp: November 25, 2019, 10:50:14 pm
content: If the resistors aren't sorted and are just in a random mess, in a bag, then they're not worth much, because resistors are so cheap, it isn't worth your time searching for the correct value.Resistors are made in standard value ranges, most commonly the E24 and E96 series. An E12 set of resistors from 10 Ohms to 1M will be sufficient for most hobby applications, since other values can easily be created by connecting them in series or parallel. An E24 set from 1Ohm to 10M will be enough to build most circuits in books, magazines, data sheets, the Internet etc.https://en.wikipedia.org/wiki/E_series_of_preferred_numbersI keep my resistors all sorted in cases, containing tubes of the different values.Awhile ago I made some tables for making E96 resistors from E24 and E24 resistors from E6/E12, but I don't use them much because it's easier to use an online calculator.https://www.qsl.net/in3otd/parallr.htmlhttp://jansson.us/resistors.html

author: wilfred
author_rank: Super Contributor
timestamp: November 25, 2019, 11:01:58 pm
content: Quote from: GlennSprigg on November 25, 2019, 12:10:00 pmJust about everyone does it. But age and in some cases wisdom arrive to snap you out of it. And lack of space and time and eyesight to sort them confidently.A small box of dreams is fine but watch it.Resistors are perhaps the most useful thing to keep. They may be cheap to buy but also they are the same effort to search out and place on the order form. Every project needs resistors.

author: SilverSolder
author_rank: Super Contributor
timestamp: November 26, 2019, 12:31:38 am
content: Quote from: jetsam on November 25, 2019, 12:57:38 pmThat's probably setting the bar very high, in reality!

author: Brumby
author_rank: Unknown
timestamp: November 26, 2019, 12:48:18 am
content: I agree.I would estimate my usage-in-anger rate at being well below 1%

author: jetsam
author_rank: Newbie
timestamp: November 26, 2019, 04:37:37 pm
content: QuoteYeah... I probably have 5% out of the storage boxes at any time, because I use a lot of breadboards, but temporary use on a breadboard doesn't count.Especially if I consider the components I won't salvage from otherwise destroyed PCB's (most resistors, anything that's got no leads left, dodgy and aging capacitors, etc...), 5% seems unlikely. Still, it's just a fuzzy goal, not really a hard target.Using 5-20% of the collection by monetary value or dollars spent is almost certainly achievable, though. Just use all your expensive components, and don't buy spares of those expensive, precision bits...

author: wilfred
author_rank: Super Contributor
timestamp: November 27, 2019, 12:49:32 am
content: Quote from: jetsam on November 26, 2019, 04:37:37 pmSure it does. You had to have the component on hand to use it even temporarily. Otherwise you'd need to buy it.

author: Brumby
author_rank: Unknown
timestamp: November 27, 2019, 01:00:41 am
content: Yes - breadboarding DOES count!Even if you try 5 different resistors in a given spot for 2 seconds before you find a value that works ... that counts as 5 components on the usage-in-anger scale - not just 1.... and to be honest, often those other resistors get lost on the bench and end up as vacuum fodder.

author: GlennSprigg
author_rank: Super Contributor
timestamp: November 27, 2019, 12:54:50 pm
content: When I'm designing stuff, or just playing around, I usually use boards like this......I have MANY of them, for types/ranges of capacitors, resistors, inductors etc., for tempsubstituting in-circuit, before deciding on the ones to use!!P.S. Re: Strange value resistors. Low/Medium grade Security systems I've worked onrequire 'special' value resistors to be detected "End Of Line" with the various sensors.You can't but them normally, and often need fairly complex series/parallel concoctionsto get close to the required values, if making your own. Stupidly, most people put themin series at the 'Panel', instead of the E.O.L. , to stop people bridging them in the Field!!Higher security systems, as in banks & prisons, had an 'electronic-module' epoxy moldedinto the field sensor/switch, and a custom singly matching 'chip' in the alarm panel !!(ALL matching modules/chips for each circuit is unique in the World)

author: james_s
author_rank: Super Contributor
timestamp: November 27, 2019, 06:16:23 pm
content: Having a special value resistor in the sensor seems a bit silly, a 50 cent pot can be any value resistor you want and a multi-turn trimmer can be set quite accurately.

author: GlennSprigg
author_rank: Super Contributor
timestamp: November 28, 2019, 02:55:36 am
content: Quote from: james_s on November 27, 2019, 06:16:23 pmYes, but you need to know the value first!!

author: james_s
author_rank: Super Contributor
timestamp: November 28, 2019, 03:50:00 am
content: Quote from: GlennSprigg on November 28, 2019, 02:55:36 amMeasure the voltage across the sensor? I don't know a lot about alarm systems but even if they used ordinary off the shelf resistors you'd still have to know the value.

author: bob91343
author_rank: Super Contributor
timestamp: November 28, 2019, 04:19:59 am
content: All these comments made me chuckle. As it happens, I also have tons of components salvaged from otherwise useless gear. Having said that, nobody gave my reason for doing it.I very much enjoy disassembling equipment, and I very much enjoy measuring parts values. I compare readings from various measuring devices. I love my hot air soldering tool and it's fun to see if my HP and GR (and so on) measuring devices agree, and how much difference I see. I learn how to connect the parts for consistent readings, too.I have some of these 'kelvin clips' that not only work for their intended purpose but also can be used singly to test surface mount parts.Yes I have installed parts backwards. It can be tricky to find the problem. You can also ruin stuff, which I have done too.This is a hobby, at least for me.

author: jetsam
author_rank: Newbie
timestamp: November 28, 2019, 05:03:44 pm
content: I enjoy disassembly for its own sake as well. I used to hate difficult salvage of multi-legged components, but I got a cheap Velleman soldering iron/sucker which works better than I was expecting it to... now I quite like the challenge of a USB connector or a 6 terminal transformer.On the list for Xmas wishes: hot air and surface mount salvage gear. Do you have any recommendations in the cheap-as-can-be range? I'm thinking a cheap-*** Chinese clone rework station, maybe a hot plate, some thermal protection for me (full ski mask style eye protection and oven gloves(??)), and a second fire extinguisher for the area...Have you been able to salvage and reuse surface mount chips of modest size? I'd like to be able to use the 6 to say 32 pin jobbies in other projects with breakout boards at first, maybe pcb's later...cheers,jetsam

author: SilverSolder
author_rank: Super Contributor
timestamp: November 28, 2019, 05:16:55 pm
content: There is definitely something pleasant about recycling electronic junk... sadly, you end up with an even larger collection of parts that you then end up using <5% of! :-)It is indeed good practice to measure components on junk boards (both in and out of circuit) to develop your "feel" for how things are supposed to work.

author: GlennSprigg
author_rank: Super Contributor
timestamp: November 29, 2019, 11:43:13 am
content: Quote from: james_s on November 28, 2019, 03:50:00 amHi James.... I think you missed the original point, so I'll explainFor those more elementary alarm systems, the equipment manufacturers tell you, and 'give' you, the customspecial value EOL resistors, and values. This simplistic 'method' was only a basic deterrent to stop peoplefrom 'trying' off-the-shelf resistors, to bypass the circuit. We only had to make our own, if we didn't have onehandy, and we 'know' what the expected value is for that particular alarm panel. They had quite a smallmargin for error!! Slightly too high resistance signals an alarm. Slightly too low causes a Tamper alarm.(The circuits are normally-closed (with resistor in series) for a no-alarm condition).Have a great day. Glenn

author: james_s
author_rank: Super Contributor
timestamp: November 29, 2019, 07:22:52 pm
content: Quote from: jetsam on November 28, 2019, 05:03:44 pmWith hot air it's trivial to remove surface mount ICs with hundreds of pins, I've salvaged 208 pin QFPs with a heat gun but a proper temperature controlled hot air station is better. I usually do the removal with hot air and solder them with an iron and flux.A vacuum desoldering gun makes through-hole parts easy, I can remove 40 pin DIP ICs from a double sided board on a whim in a couple of minutes.For salvaging parts from a scrap board I've often used a heat gun, the sort used for stripping paint and thawing pipes. Set the scrap board upside down over the bench suspended between a couple scraps of wood, heat an area of the bottom with the heat gun and then whack it with a stick and parts will rain out of it onto the bench. It's brutal and smelly but fast and efficient. Make sure you have good ventilation and try not to cook the board so much that it burns and stinks.

author: Dacke
author_rank: Regular Contributor
timestamp: November 29, 2019, 11:10:50 pm
content: Quote from: jetsam on November 28, 2019, 05:03:44 pmIf you're talking about the cheap hot air stations in the $35-$65 range that all have the same design but dozens of different brand names on them, those things scare me. I've probably seen half a dozen videos over the past year of those things just sitting on the bench not being used and randomly having a complete meltdown, over heating and catching fire. Some people may have great experiences with them, but I just don't want to risk something like that happening in my home especially if I step away from the bench for a bit. I can't afford a professional rework station either, so I compromised and bought a Quick 957DW+ rework station about a year ago, I think I paid maybe $110 for it new from Digikey but I still consider it a cheapo station. But even with this one, I still think about it spontaneously just going up in flames so I always keep an eye on it if I'm using it. This all could be just my paranoia though.