From: firstname.lastname@example.org (The little lost angel)
Subject: Re: How to make/solder a circuit fast?
Date: Tue, 24 Sep 2002 17:04:42 GMT
Organization: Yes please, I'm quite disorganized & lost at the moment
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NNTP-Posting-Date: Tue, 24 Sep 2002 17:03:14 +0000 (UTC)
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On 24 Sep 2002 08:59:32 -0700, firstname.lastname@example.org (N. Thornton) wrote:
>Pretty much, if its 0.75v dc, the screen will show zero. Soundcard PC
>scopes will show you the waveform correctly, at least upto their
>frequency limit, but they dont show the dc offset. So a square wave of
>0v and 5v would appear the same as a square wave of -2.5v and +2.5v.
>They are far from ideal, but whats a soundcard cost, 6GBP for a new
>one. Still pretty useful.
*nodz* Though I'm still saving up for a proper DAQ because my hobby
project will need much more than what the soundcard can do for me.
>One of my classic stories :) A light bulb will indicate voltage and/or
>current, and can be used in series with something to prevent it
>shorting its supply, which very much helps to find out where the fault
>is when all that happens is the fuse pops.
How does it do that?
I've seen a strange setup that the tech guys rigged up and used in my
previous company which dealt with tech stuff. There's a light bulb
connected to the AC main, a normal household wall switch box with two
They connect this to a equipment reported as faulty, switch it on,
flips the two switches in some sequence. And announces if the
equipment was shorted internally or not by looking if the bulb lights
>I would check out the seller profiles carefully. I'm not that
>impressed with online auctions.
Generally MOST of them have excellent profiles.
Unfortunately I also heard from my friends that often if a seller gets
more than what he expects, or a small problem crops up, they "buy"
good rating from the buyer by offering each other good ratings and a
>Maybe. The reg would be the first in line to die I guess. If it is a
I took a Fluke and connected to the driver output. of course it's a
DVM but it also had a Hz function. 0 Hz, does that means it's not a
>Mmm, looks like you're right. Of course it isn't quite that
>simple....groan... a diode will have leakage curent, and only if that
>is significantly smaller than the leakage of the other bits will the
>reg & LED see very little reverse voltage. But that is most likely so,
>so probably would do it yes.
How do I choose a diode? I wouldn't want to interfer with the forward
flow at all, so I have to pick a low forward drop. The fan is expected
to draw a nominal 0.3A but I expect it to peak at double that during
startup, so 600mA.
Assuming I pick a 1V forward drop, the diode would need to dissipate
0.6W rite? So a 1W diode should do no? And I should pick as low a
forward drop diode as possible since higher forward drop means more
power dissipated no?
>> I've also read that capacitors are used as
>> buffers in passive PFC which mentions inductance?
>OK you got me puzzled there. :)
When I was reading up on Power Factor Correction, one of the things
that came up was that capacitors can be used to provide PFC. Since PFC
was explained with things doing with inductance and what not, I
thought maybe the capacitors would buffer against inductance?