[Techtalk] Soldering irons (OT?)

R. Daneel Olivaw linuxchix at r-daneel.com
Sun Jan 11 15:51:38 EST 2004


Hi there,

> > I've been to Dick Smith's electronics, and my question is:
> > Do I get a 25 watt soldering iron, or a 40 watt?  Particularly with
> > things like linking the jumpers required to flash the bios on a
> > Xbox, it is not clear to me that 'bigger is better'.  Or do I get
> > both?
> Mine is a 25-watt Weller with changeable tips.  One's very narrow,
> one's wider.  IMO, 25 watts is plenty enought to fry ICs.

I would also agree that 25W is quite enough for electronics. Bigger ones
will get you in trouble : heating too fast & too much. Also bigger ones
have bigger tips, and you might need very narrow ones for small
electronics (electronics have evolved to very small parts, so you may
also invest in a magnifying glass ;p) You may have a look at some
soldering irons that have a control button, so you can "heat on demand"
without unplugging the iron to stop power consumption, that is a really
nice feature.

> > And on a similar vein, muti-meters.  There were some cheap ones
> > (under AUD$50) and there were quite a few expensive ones (over
> > AUD$100).  I'm currently assuming that a cheap one is fine for
> > learning with, but is it worth investing in a good one?
> 
> Well, the expensive stuff is very nice to look at (and to use), but my
> father gave me this lecture about a voltmeter's internal resistance
> (and why it's good to be a large number), and in a similar vein, why
> an ampmeter should have a very low internal resistance.  I remember
> those two numbers are important.

As far as I remember, these 2 values have a logical meaning :
Voltage measures are done in parallel to components, so as you "add" a
circuit parallel to your component, the best way NOT to interfere with
the component's measure is to have an (theoretically) infinite
impedance.
The ampmeter measure is done serially, and you don't want
your ampmeter to consume any current (I=Z/U), so it's internal impedance
should be null.

have a nice tim with electronics :)

R. Daneel Olivaw,
The Robot Inside.

> Ei elämä ole vaikeaa,
> se on mahdotonta.  Ja se tapahtuu.
>                                                  Lassi Nummi

err, this means ? ;)


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