[sdiy] Useful equipment

Fri Aug 2 22:07:19 CEST 2002

    There are a lot of opinions on that subject...my preferences is that the Iron should have a high heat capacity (this is not the same as temperature).  You
want to make the solder connection as quickly as posible, and it takes a lot of heat to do that.  If you have to keep the iron on the connection for a long
period of time to get the pieces hot enough to solder, you don't have enough heat.

    Temperature controlled irons, of course, help a lot.  When you touch the tip of the iron to the connection, it will pour more power in (more heat).

    Before I could afford to purchase a temp controlled iron, I used to use a 47 watt unger soldering pencil.  Now, while this thing had plenty of heat, it
also got really hot (high temperature) as well, and that would tend to cause the tinning to burn off.  It was a real pain if I accidently left it on over
night.  Getting the tip re-tinned as not fun.  The little 25 watt pencil did not have the problem with burning the tip, but, on some things it just could not
get the parts heated up quickly enough.

    So, in my opinion, the best setup is to have some sort of a temperature controlled iron, if you can aford it.  Otherwise, use a standard iron with the
highest wattage you are comfortable with (probably not more than 47 watts, any bigger an the irons get unwieldly).

    As far as temp controlled irons go, I use the Weller WTCPN iron.  The temperature is set by the tip (no knobs).  I am not too sure if getting one of these
used is a good idea.  It is expensive to repair them if they don't work.  Probably one of the newer electronic models (the ones with a knob) might be a better
choice.  Hopefully, there will be other opinions about this...

Steve Begin wrote:

> What constitutes a good soldering iron?  I'm guessing mine is far from it, since it was under 10 dollars CAN. :)
>
> I'm on a budget, but I'm willing to spend more than I should, if it comes to that :)
> Thanks for all the great advice, I'm gonna be spending the next week or so glued to ebay, and see if I can't get a decent selection of equipment out of it!
>
> > Steve Begin
>
> -----Original Message-----
> From: Neil Johnson [mailto:nej22 at hermes.cam.ac.uk]
> Sent: Friday, August 02, 2002 2:19 PM
> To: Steve Begin
> Subject: Re: [sdiy] Useful equipment
>
> Steve,
>
> I'll assume (a) you're on a budget, (b) you're only interested in audio
> analogue, and (c) you like visual stuff (seeing things!).
>
> So, with that in mind:
>
> 1) O'scope -- ESSENTIAL!!  So you can see waveforms, and measure frequency
> fairly well, and volts too.  I think for audio 20MHz is plenty enough
> bandwidth, so 50MHz may be way too much.  Have a hunt around eBay or local
> second-hand shops.  Try the local hobbyist magazines or the internet for
> equipment resellers.  My first scope was a dual-trace 20MHz Hameg HM203-6.
> Very well made scope, still going strong after, oooh, 15 years.
>
> Certainly aim for dual channel.  Tektronix and HP make really good scopes
> (my second scope is a Tek) but they are quiet pricey.  Phillips are pretty
> good, as are Hameg (like mine).
>
> For example, there's a brand new B+K 30MHz dual-trace scope at $151 on
> eBay now.  A bit pricey, as you probably don't need *new*.
>
> I'd steer clear of the older Tektronix plug-in scopes for now---while they
> are very good, they are quite daunting for a beginner!
>
> There's a Phillips PM3232 dual-trace scope currently sitting at $10, with
> 4 days to go.
>
> LeCroy -- the Rolls Royce of the scope world -- with prices to match!!!
>
> The HP180 is a pretty good machine, robust, reliable, many around.
>
> Telequiment are pretty good too, if a little on the clunky side for my
> personal taste.  Reliable though.
>
> 2) DVM
>
> Get a good one, like Fluke or AVO.  Will last years if looked after.
> Here, I'd recommend buy new, as they might have had a brutal life before
> you get it, in which case it may be so out of calibration as to be
> virtually useless :(
>
> Beckman is a good make too.
>
> 3) A good soldering iron
>
> Essential for good joints.  Otherwise your problems will be in your
> soldering, not your understanding.
>
> 4) Breadboard
>
> Fine for trying stuff out.  One with built-in PSU and function gen might
> be good.  Or, start by learning how to make your own function generator.
> Build your own tools as you learn, that way you'll enjoy learning even
> more!!
>
> I wouldn't both with those substitution boxes, way too much bench space,
> and not much use anyway---what's the point in dialling in a resistor value
> you can't buy??!!  Anyway, once you get a feel for what values go where,
> you just won't bother with them.  I know, I have both types, haven't
> touched them in years!
>
> What's more important is a willingness to start from the basics, and to
> learn as you go along.  Start with a simple amplifier with a transistor or
> op-amp.  You can power if from a battery, and use your finger (or
> microphone) as signal source.  Look at the input signal with channel 1 of
> your scope, and the output of channel 2.  Hopefully (!) the output should
> be bigger than the input.
>
> Now add a feedback circuit to make it into an oscillator.  Understand the
> maths behind the frequency of oscillation, and the various types of
> oscillator (Wien, RC, phase-shift, etc).
>
> And so on.  AofE will guide you.
>
> Its all good fun!
>
> Hope this helps,
> Neil
>
> --
> Neil Johnson :: Computer Laboratory :: University of Cambridge ::
> http://www.njohnson.co.uk          http://www.cl.cam.ac.uk/~nej22
> ----  IEE Cambridge Branch: http://www.iee-cambridge.org.uk  ----

--
 -Jim
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