
USB soldering iron test and teardown [video] - mmastrac
https://www.youtube.com/watch?v=o-8D5t6TJYU
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ratfacemcgee
I am obsessed with big clive, mostly with his teardowns of very dangerous and
dodgy electronics.

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shmulkey18
Yes, his channel is wonderful. I love his low-key delivery; he's kind of the
anti-Dave Jones (eevblog - also excellent).

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robzyb
I feel a strong need to throw Mike of mikeselectricstuff[1] into the mix.

His dayjob involves building awesome bespoke electronics, and his vlog has
teardowns of heaps of really unique items.

Clive/Dave/Mike make up the entirety of my YouTube electronics subscriptions.

[1]
[https://www.youtube.com/user/mikeselectricstuff](https://www.youtube.com/user/mikeselectricstuff)

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deelowe
Mike is great, but I can't understand a word he's saying half the time.

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fuzzieozzie
Pleasantly surprising to see it actually works (even if on an isolated power
supply for safety)

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voltagex_
I don't really understand how there's 120V at the tip when it's plugged into
the Apple USB powers supply. Isn't there a gap between the AC and DC
electronics?

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foldr
It's normal for these sorts of power supplies to have a small leakage current.
Hopefully someone else will be able to explain the details, but as I
understand it it's the result of capacitative coupling across the transformer
and filter capacitors.

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cellularmitosis
I can't explain the details, but I was able to measure the current.
Interesting that I didn't measure any current from a genuine Apple charger,
but enough current to cause a tingle from the cheap import chargers.
[https://www.youtube.com/watch?v=pjz4I69YoUA](https://www.youtube.com/watch?v=pjz4I69YoUA)

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c22
> but enough current to cause a tingle from the cheap import chargers.

You should try using a multimeter!

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cellularmitosis
Um, I did, as shown in the video...

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timonoko
I have an earlier version without the movement sensor. It does not work too
well in far-out places, because there is no AC or radio field to trigger the
555. I mended this by adding another button connected to USB-minus. My hand
now closes the circuit and causes negative edge which triggers the 555.

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kevindeasis
A question that comes often from a bunch of young people is that they ask me
about where to start learning about hardware, soldering, leading into
networking (TCP/IP, BGP, etc).

I don't really know how to answer their question.

Does anyone know what I should tell them for future reference if these things
keep coming up?

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joshvm
Arduino is the de facto starting place for new hobbyists. It's a very low
barrier to entry and runs on pretty much anything.

If you want to learn networking at an Internet of Things level, look at the
Spark Photon (basically an ARM dev board with a TI CC3000 WiFi module). It's
only $19. The documentation is fantastic, hence I would recommend it over say
the ESP2866 which is super cheap but a bit more... hacky.

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makomk
I think they actually switched away from the TI CC3000 module with the Photon
because it had some quite severe, unfixable firmware issues.

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collyw
(Software person here, so excuse my ignorance). If you run one of these via a
laptop USB, won't it put a lot of stress (heat) on the power / usb circuitry?
The soldering iron end is basically using all that current to generate heat so
my assumption is that the current flowing through the circuits will have some
sort of heating effect as well. I always assumed USB was for relatively low
power appliances.

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pluma
Let's put it this way: if you attached a light bulb (which can get fairly hot)
to USB, would you expect the same problem? What about plugging a soldering
iron in the wall plug -- would you expect that to heat the socket (and cable)?

It's not the current that makes it hot, it's how the current flows through it.

EDIT: It's basically about resistance (the things that get hot are the
resistors):
[https://en.wikipedia.org/wiki/Electric_heating](https://en.wikipedia.org/wiki/Electric_heating)

EDIT2: I'm not an electronics person either. Please feel free to correct me if
I'm grossly misrepresenting how things work.

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LeifCarrotson
And by "fairly hot", you might use as an example the tungsten filament in a
Christmas light bulb - which can be 2500 C!

Power (and therefore heat) is current squared times resistance, or
equivalently voltage drop times current. A copper wire or PCB trace has very
low resistance, and a soldering iron tip or thin tungsten filament has high
resistance, so one stays cool while the other gets hot.

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collyw
Ok, thanks for clearing it up. I had kind of assumed PCB trace would have some
resistance due to the relatively small size of it (compared to say a cable on
an electric appliance), but I guess the heat is coming from the soldering iron
tip and doesn't need to be huge to get it hot.

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StavrosK
So what does this mean? Do I get one of these or what?!

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MindTwister
If he didn't like it you would know it:
[https://www.youtube.com/watch?v=ASnLL6ebaco](https://www.youtube.com/watch?v=ASnLL6ebaco)

In the end you need to balance the pros and cons and see which comes up on top
in your particular use case.

Personally, for my use cases (field repair of RC gear), I might buy one after
this review.

