Search found 15 matches

by FOB
Sat Oct 01, 2011 6:42 pm
Forum: General Discussion
Topic: voltage regulator with crow bar protection
Replies: 10
Views: 3095

Re: voltage regulator with crow bar protection

Back in the 80's and 90's most of the guys in the local Ham radio club would rely on the ASTRON brand of power supplies. Most models used the same pc board for voltage control, foldback current, and an SCR circuit (crowbar) to protect from catastrophic overvoltage. One of the guys designed a pc boar...
by FOB
Wed Jan 06, 2010 10:20 am
Forum: General Discussion
Topic: New to electornics
Replies: 22
Views: 4446

Re: New to electornics

Go to Forrest Mimms website and invest in his "Getting started in Electronics" or his "Engineers Notebook" He has been writing books in a no-nonsense easy to understand way for at least 30 years. There are projects and building blocks ..... not just soldering projects. Most of the stuff his books ca...
by FOB
Fri Jun 26, 2009 9:16 am
Forum: General Discussion
Topic: Ramsey FM transmitter advice
Replies: 5
Views: 1384

Re: Ramsey FM transmitter advice

I built one several years ago...still works. 25 mW covers my entire yard (9 acres) furthest point from the house is about 900 ft. I used 107.7 Mhz cuz there was nothing there. I usually drive it with a cd player going thru an amp with line level out. The only problem I remember was during constructi...
by FOB
Fri Apr 03, 2009 12:53 pm
Forum: General Discussion
Topic: Perimeter Intrusion Detection
Replies: 17
Views: 3299

Re: Perimeter Intrusion Detection

You could always use the good old trip wire with a noisemaker instead of the hand grenades we used in Southeast Asia. Why not an IR laser? If they can't see it they won't know they were detected . Who's gonna look at a knee high laser (that is invisible) anyway? My sympathy is with you ...I think va...
by FOB
Fri Mar 13, 2009 4:07 am
Forum: General Discussion
Topic: Dremel "WorkStation" ?
Replies: 26
Views: 4808

Re: Dremel "WorkStation" ?

Hi there, Sounds interesting. Wow, several hundred boards? What was that for, to back the article? The article was for an auto shut-off for a soldering iron. I got tired of burning up tips because I got called away from the bench for extended periods. I showed it to the Ham club at a meeting, and se...
by FOB
Thu Mar 12, 2009 7:59 am
Forum: General Discussion
Topic: Dremel "WorkStation" ?
Replies: 26
Views: 4808

Re: Dremel "WorkStation" ?

Back in "88" I put together an article for 73 magazine and provided a pc board for the project. I learned two things, 1.) I wasn't gonna get rich as an author, 2.) Making several hundred PC boards takes longer than I thought it would. But the Dremel tool and drill press device was a big help. It was...
by FOB
Fri Feb 06, 2009 4:26 am
Forum: General Discussion
Topic: Surplus Sales
Replies: 2
Views: 961

Surplus Sales

The serious WEB surfers probably know this, but most of us "Hobby Grade" types may not, the U.S. Government runs an Ebay type auction site where they sell everything from electronic test equipment, to scrap B-52's. They charge sales tax (local-state), and don't deliver, but if you are within driving...
by FOB
Thu Feb 05, 2009 3:51 am
Forum: General Discussion
Topic: Ice Storm
Replies: 28
Views: 4492

Re: Ice Storm

Here's my 2 cents worth. My first interest in portable power came in 1995 to power the two a/c units I put on an old school bus I converted to a camper to take to hamfests and tailgate. I bought a twin cyl. 19 HP 10KW ($2,000.00) so it would not stall if both a/c units started at the same time. It w...
by FOB
Thu Aug 21, 2008 10:08 am
Forum: General Discussion
Topic: Parts I.D.
Replies: 2
Views: 1282

Yup you are right.....I just copied a return address from something they sent me without checking...and I know better than that.
by FOB
Thu Aug 21, 2008 4:00 am
Forum: General Discussion
Topic: Parts I.D.
Replies: 2
Views: 1282

Parts I.D.

This has probably been done before, but I haven't seen it and there seem to be a lot of people looking to ID parts. IC Master used to be a set of three or four large books that came out every year with an industrial strength price tag. Now they are online and free, although they like you to register...
by FOB
Wed Jun 11, 2008 5:11 am
Forum: General Discussion
Topic: * WANTED / Needed * Battery Charger 36 volts @ +/- 20amps
Replies: 3
Views: 1461

You have probably already thought of this, but ..... Most control voltage in industrial situations is 120 VAC. A 5kva 480vac (primary) to 120vac (secondary) is pretty common and while pricey when new, there is not much resale value. If you put 120vac on the primary, you will get around 30 vac out wh...
by FOB
Wed Jun 11, 2008 4:21 am
Forum: General Discussion
Topic: Need a momentary switch to switch about 40 amps to a DC moto
Replies: 7
Views: 2228

Back in the 1970's before commercial model starters were common, we used windshield wiper motors available from salvage yards for less than $5.00. We used flipper switches from old pinball machines to switch the wiper motor. Similar switches are available, I believe, at All Electronics and other sur...
by FOB
Mon Apr 21, 2008 9:22 am
Forum: General Discussion
Topic: Blue transfer paper
Replies: 21
Views: 4985

PC Transfers

Unless it absolutely has to be pretty, why use the computer printout? You could probably draw it up with a sharpie pen in less than 15 minutes. Make a copy of the foil side, tape it to the foil side of the board, drill the holes, connect the holes with sharpie, go over it again after it dries. If yo...
by FOB
Wed Jan 16, 2008 10:22 am
Forum: General Discussion
Topic: weird power problem
Replies: 29
Views: 7557

Wierd Power

Did the circuit work OK before the PC was installed? Will the breaker reset and stay set after it trips or do you have to shut off your PC? You can buy a plug in device that will tell you if the wiring is correct for less than $10 at Home Depot or any electrical supplier. Do you have any friends int...
by FOB
Thu Nov 29, 2007 10:24 am
Forum: Up For Grabs
Topic: Wanted in trade...
Replies: 5
Views: 4181

I'm interested in the Kenwood 7800 .... do you have a price in mind? I don't have what you want to trade.[/list]