Search found 340 matches

by terri
Tue Sep 13, 2005 6:09 am
Forum: General Discussion
Topic: where does the power go?
Replies: 80
Views: 17302

Re: where does the power go?

That's the difference between "precision" and "accuracy."<p>I have a bathroom scale which gives a very precise result to 1 decimal place, but it's inaccurate by about 10 lbs. on some days.<p>Whoa! This morning it's off by 11 lbs. Surely it wasn't that cake someone left in the break room yesterday!
by terri
Tue Sep 13, 2005 1:53 am
Forum: General Discussion
Topic: Standard IF frequencies
Replies: 3
Views: 784

Re: Standard IF frequencies

Some old 1940-1950 TV sets used a 14MHz first conversion IF and it was big problem since it sat smack in the middle of the 20 Meter ham band. So every time a ham keyed up, it played hob with TV reception for owners of that brand. Of course, it was always the ham's fault, not the bonehead who chose t...
by terri
Tue Sep 13, 2005 1:07 am
Forum: General Discussion
Topic: How to size Transformer
Replies: 21
Views: 4054

Re: How to size Transformer

The transformer ought to have about 2-3/4 square inches of core to handle 250 watts without transformer saturation, according to the ARRL Handbook. This is about 1-5/8 inches on a side for the central part of the transformer core.<p>250 Watts does seem like a lot, but on the other hand, there's a lo...
by terri
Tue Sep 13, 2005 12:02 am
Forum: General Discussion
Topic: where does the power go?
Replies: 80
Views: 17302

Re: where does the power go?

Yes, it takes power to turn a loaded generator. Even a little 7 watt bicycle generator can be felt when you turn on the bike lamps. And, before computer-controlled idling, turning the headlights on in a car would result in a 60-70 RPM drop in the idle --certainly noticeable.<p>And for many decades h...
by terri
Sun Sep 11, 2005 10:39 pm
Forum: General Discussion
Topic: where does the power go?
Replies: 80
Views: 17302

Re: where does the power go?

You sure you didn't misread the decimal point on the "5 HP?"<p> That's about 3,000 watts, just doing it in my head. I thought most alternators and generators put out, ohhh, say 50-110 watts in passenger vehicles.<p> Even considering belt and other friction losses, that sure seems high to me. Even if...
by terri
Sun Sep 11, 2005 8:23 am
Forum: General Discussion
Topic: Forget Hydrogen
Replies: 70
Views: 14295

Re: Forget Hydrogen

Well, thanks. An interesting aside. I guess maybe now we should go back to the subject of "creating" hydrogen out of nothing. <p>
I don't see what the big problem is. All you've got to do is mix a bucket of electrons with a bucket of protons and you get two buckets of hydrogen.<p>
Right?
by terri
Sat Sep 10, 2005 2:40 pm
Forum: General Discussion
Topic: Forget Hydrogen
Replies: 70
Views: 14295

Re: Forget Hydrogen

"You were supposed to use peanut oil because it wouldn’t diesel on its own." That's interesting. Was this a MFR recommendation? Seems to me although it might not diesel, it sure would oxidize over time, like linseed oil, and gum up the works... Yes? No?<p>I use the Crosman Pellgun oil, because it se...
by terri
Sat Sep 10, 2005 12:34 pm
Forum: General Discussion
Topic: Generate 7w of electricity by walking
Replies: 33
Views: 4651

Re: Generate 7w of electricity by walking

(OK, OK, challenge me on "batteries" versus "cells." C'mon, c'mon, I dare ya... I double-dog-triple-dare ya. I'll fightcha with one paw tied behind my back. I'll fightcha on one foot, I'll fightcha with my eyes closed... C'mooooonnnn, c'monnnnnn!")<p>(Cf Bert Lahr as the Lion in Wizard of Oz.)
by terri
Sat Sep 10, 2005 12:30 pm
Forum: General Discussion
Topic: Generate 7w of electricity by walking
Replies: 33
Views: 4651

Re: Generate 7w of electricity by walking

Wal-K-TargMart has AA batteries on sale.
by terri
Sat Sep 10, 2005 12:09 pm
Forum: General Discussion
Topic: new rpm sensor
Replies: 17
Views: 2631

Re: new rpm sensor

I went through this a while ago with the questions on cutters. Turned out the querent was cutting sections out of termite hills for some research or other. Put a whole different light on the query!<p>One of the most important aspects of questioning on this forum is to state your application , that i...
by terri
Sat Sep 10, 2005 11:26 am
Forum: General Discussion
Topic: Ungar parts needed
Replies: 5
Views: 1502

Re: Ungar parts needed

Here's the link to the first Whatley article:<p> http://206.131.241.58/ubb/ultimatebb.php?ubb=get_topic&f=1&t=002631 <p>Scroll down to the 07 Mar 2005 posting by Edd. Lots of good info, although the topic started with Weller stations.<p>Here's the link to the second Whatley article, which is on the ...
by terri
Sat Sep 10, 2005 7:43 am
Forum: General Discussion
Topic: Forget Hydrogen
Replies: 70
Views: 14295

Re: Forget Hydrogen

Yeah, I've got an ancient Feinwerkebau cal .177 air rifle which, if you oil it a little too much, "diesels" on firing. This one was built in the days when men were men and air rifle springs were air rifle springs.<p>Takes a lot more effort to cock the thing than any modern air rifle... which look ex...
by terri
Fri Sep 09, 2005 5:19 pm
Forum: General Discussion
Topic: Forget Hydrogen
Replies: 70
Views: 14295

Re: Forget Hydrogen

How about one of the earliest: The Brush carburetor.<p>This gem had a rotating brush partly immersed in a pool of fuel, and then the brush ran against a sharp edge to create the spray in the intake air stream. Circa 1905-1920 or so. I wish I still had the book I saw this one in. <p> This same old bo...
by terri
Fri Sep 09, 2005 5:03 pm
Forum: General Discussion
Topic: Fuse problems
Replies: 18
Views: 3516

Re: Fuse problems

If it was running right in the first place. As I said, in this case, we know why the fuse blew. If one did not know why it blew, sticking am ammeter in the circuit would be just like running it with no fuse at all, except of course for the fuse in the ammeter itself. <p>The advice about calculating...
by terri
Thu Sep 08, 2005 11:46 pm
Forum: General Discussion
Topic: temperature sensor
Replies: 18
Views: 2854

Re: temperature sensor

http://www.national.com/pf/LM/LM34.html <p>These are so cheap it's ridiculous. Try allelectronics.com<p>Bear in mind that a good design chief is well aware of the relative costs of having a functional circuit designed in-house versus the cost of an off-the shelf gizmo that does the same thing.<p>Yo...