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Beginners / Re: Some noob questions
« Last post by KL27x on Today at 02:49:01 pm »
The water analogy isn't sorta kinda a half-ass analogy. It is pretty close to perfect.

A high pressure washer and your kitchen faucet might produce the same volume of water per time, but the water coming out of the high pressure washer has more velocity. Thus, it has more kinetic energy. Thus, it can do more work.

In the water analogy, it is most common to refer to the height of the water as a measure of its potential energy. But if you were to pour it to "ground," that turns into kinetic energy. In absence of "resistance," 1 gallon of water poured from 100 feet high would be moving faster by the time it reaches the ground than 1 gallon of water poured from 3 feet.

So, this is why hydroelectric generators are positioned at the bottom of tall water falls, not just stuck in the middle of a big, slow moving river that passes 1000x the volume of water per unit time.

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Test Equipment / Re: bg7tbl gpsdo master reference
« Last post by KA1J on Today at 02:42:46 pm »
Folks,

I have a BG7TBL 2015-09-17 with the oscilloquartz  OCXO & U-Blox GPS. I was able to have this one evaluated when I got it and it was surprisingly stable and accurate.

I'd like to find another one like this for my 2nd radio but this BG7TBL version isn't available as a couple years back. I need the 10MHz for calibrating my Ham Radio stability and the GPS via RS-232 keeps my computer synced using NMEATime. There's now a few more modern versions of this GPSDO but I have no idea if they are unreliable junk or worth buying.

I'd appreciate opinions on what is current, offers what I need and is relatively inexpensive. I'll be more than happy with another BG7TBL if it's as good as the one I have but anything trustworthy will be fine.

Thanks.

Gary
KA1J
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Crowd Funded Projects / Re: Vion : The Worlds Silliest Multimeter
« Last post by EEVblog on Today at 02:40:07 pm »
I just noticed in the Kickstarter comments that they are now hoping to bring to supporters "the best multimeter ever", I wish them the best of luck with that ridiculous promise, also one of the backers has asked about the Apple App Certification without a reply to date so that could be a hurdle for them as well.

Having just gone through that, it's not quick nor easy.
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Crowd Funded Projects / Re: Vion : The Worlds Silliest Multimeter
« Last post by EEVblog on Today at 02:39:17 pm »
A multimeter with completely wireless probes would be nice.  :bullshit:

Done that:
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General Chat / Re: Ever wonder if you are in the wrong job?
« Last post by EEVblog on Today at 02:37:08 pm »
If you mine them all, they will be worthless.

Diamonds are already worthless, try go actually sell one...
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Repair / Re: Fluke 179 1.5mA battery current in sleep mode.
« Last post by skripach on Today at 02:34:43 pm »
The device does not have a supercapacitor. In the operating mode it seems to work well, the current is about 2 - 2.5 mA, the problem is only in sleep mode. Any ideas?
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General Chat / Re: Ever wonder if you are in the wrong job?
« Last post by Brumby on Today at 02:32:51 pm »
Yes.  You would be better off cornering the market in shovels.  Make a mint, you would.
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Beginners / Re: Some noob questions
« Last post by Jwillis on Today at 02:30:28 pm »
With the analogy, flow is defined as an amount over time. Speed is not a factor in the "flow" of electrons .We'll use yet another analogy to explain .Think of a Newtons cradle and that best represents how electrons move down a wire.Although in reality its much more chaotic with many other factors . Analogies are used to to best explain a process in the simplest terms.Its much easier to picture in the mind something that may be familiar.
It's not an attempt to insult your intelligence in any way.Just a simple way to explain the relationship between voltage , current and resistance .
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Test Equipment / Re: LeCroy 9350AM - Inverted CRT Image
« Last post by floobydust on Today at 02:27:26 pm »
To me that is not inverted video- The CRT is just biased full on, with phosphor burns for the darker areas.
I don't see any modulation of the CRT beam or blanking, aside from the slightly brighter sawtooth lines.

If it's a video monitor, I would check at the brightness/contrast controls and see if they do anything.
A shorted video driver transistor (depends if CRT is cathode or grid-driven), or loss of DC bias for CRT cutoff is what I would look for.
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Metrology / Re: Datum 4040A Problems
« Last post by EMUD on Today at 02:19:36 pm »
Hi Ed,
first I thought, what a strange idea to shift the frequency with a signal generator ... but, it works ! I have added the results the 4040a is able to generate a positive and negative EFT ! I have added the results.

I think it is fact that the osc is not guilty !  I will check the pwr supply next.

Best regards

EMUD
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