Is it Worth Keeping/Buying as Stock? - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 25, 2012, 11:59:20 am
content: from last night i've been looking into this guy's inventory in ebay (3000++ ee parts, still looking)...http://stores.ebay.com.my/ICMarket2009came across several items, but not sure if its worth to buy to keep in stock. i wonder how frequent and in what area they are used in electronic circuit...1) shift register2) digital potentiometer3) digital switchany idea and suggestion above and which parts should i get?

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 25, 2012, 12:25:44 pm
content: the main reason for the seller, because i'm looking for higher all-round performance general opamp. tl072 is the first choice and found that seller have that, 100% feedback and... china supply free shippingso i will look for another item for combined shipping.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 25, 2012, 12:39:16 pm
content: other thing:1) voltage to frequencycounter2) flip flop (sound familiar isnt it, well i'm a newbie)

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 25, 2012, 02:02:42 pm
content: well, i always going mad when i just want to order 1 component from ebay. only few $ will turn out to be 100s.

author: sorin
author_rank: Frequent Contributor
timestamp: February 25, 2012, 02:48:17 pm
content: try withhttp://www.taydaelectronics.com/is very coll

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 25, 2012, 06:34:17 pm
content: Quote from: sorin on February 25, 2012, 02:48:17 pmthanks, bookmarked.

author: SeanB
author_rank: Super Contributor
timestamp: February 25, 2012, 07:03:03 pm
content: I do have a lifetime supply of 12V and 24v zeners, as I bought a bandolier of each at an auction years ago. I use them as regular small signal diodes quite often. They work well at this, and a few dozen have been destroyed by being driven by a 12V battery, they glow bright red for a few seconds before melting.

author: TerminalJack505
author_rank: Super Contributor
timestamp: February 25, 2012, 08:05:17 pm
content: Quote from: SeanB on February 25, 2012, 07:03:03 pmOne of the companies I worked for about 20 years ago threw away a ton of ICs and whatnot. I was given the task of throwing the stuff away so, needless to say, all that stuff made its way to my car instead of the dumpster and I ended up with a bunch of stuff that I'm sure I'll never use. Mostly 74LSxx, 74HCTxx and 74HCxx ICs. Over 100 74LS32 2-input OR gates, for example. And a ton of various sockets.I was going through those ICs the other day and, to my surprise, there was a tube of 9 AD7548BQ 12-bit DACs.I've also got a bunch of GAL16V8 and GAL22V10 chips that I pulled from god-knows-what. I probably need to give them away since I have this vague notion that I should build a programmer for them and do something useful with them.

author: wkb
author_rank: Super Contributor
timestamp: February 25, 2012, 10:40:53 pm
content: Quote from: TerminalJack505 on February 25, 2012, 08:05:17 pmThat soundsveryfamiliar. I have a ton of various TTL variants that came my way when the company I worked for at the time stopped in-house hardware development. The whole stock of components was thrown out. I have a nice subset of that at home (it was more like a truckload they threw away) Somebody want a bunch of pingrid wirewrap sockets maybe?The other day a 74F04 found its way into my Rb-oscillator to drive a bicolor LED hanging off the Rb-Locked signal.

author: amspire
author_rank: Super Contributor
timestamp: February 25, 2012, 11:09:05 pm
content: Quote from: TerminalJack505 on February 25, 2012, 08:05:17 pmYou wouldn't bother building a programmer - most cheap eprom programmers will program them and I am not sure that the programming algorithm was every publicly released..They are actually really versatile chips, and I have few tubes of the similar PEEL18V8 chips as it is handy when I need some logic in a breadboard. They are reprogrammable, so you just keep reusing them. You can usually replace a whole lot of 74 family chips with a GAL and the chip is simple enough to make the design and programming very quick. Once you get to know them, you can usually do more complex logic then you would think you can get from 8 or 10 macrocells.The problem with them though is the current - usually over 50mA doing nothing. I think that is the reason the PEELs and the GALs have become obsolete. So very useful as a way to be able to come up with custom logic chips on the spot to test an idea, but you probably will not want to use them in a final design.Richard.

author: TerminalJack505
author_rank: Super Contributor
timestamp: February 26, 2012, 12:02:52 am
content: Well great. Now you have me shopping for a programmer. See what you've done.

author: amspire
author_rank: Super Contributor
timestamp: February 26, 2012, 01:04:02 am
content: It looks like it is possible to make your own GAL programmer:http://elm-chan.org/works/pgal/report_e.htmlhttp://home.planet.nl/~havinga1/programmer/programmer.htmHaving an eprom programmer is pretty handy anyway, but I haven't seen a DIY GAL programmer design before.Next you need to find a program to write (and often simulate) the GAL device and to generate the JEDEC output file that you will used with the programmer.. There used to be lots of free solutions, but I am not sure what is available now. The first link above includes something called a "GAL Assembler" that might be a basic tool for the task.I will see what I can find.Richard.

author: amspire
author_rank: Super Contributor
timestamp: February 26, 2012, 01:23:58 am
content: It looks like Atmel WinCUPL is probably the go for designing GALs.http://www.atmel.com/tools/WINCUPL.aspx(you have to register for a free download)Here is a tutorial:http://www.engr.iupui.edu/~reid/eet155/155_lab_5.html

author: TerminalJack505
author_rank: Super Contributor
timestamp: February 26, 2012, 01:29:33 am
content: Quote from: amspire on February 26, 2012, 01:23:58 amThanks for all the info. Much obliged.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 26, 2012, 10:50:49 am
content: ok! order finalized. only a few opamps and resistors, typical stuffs. thanks guys for suggestion.