Electronics project notes/Soldering notes

⚠ This is for beginners and very much by a beginner / hobbyist It's intended to get an intuitive overview for hobbyist needs. It may get you started, but to be able to do anything remotely clever, follow a proper course or read a good book. Some basics and reference: Volts, amps, energy, power · batteries · resistors · transistors · fuses · diodes · capacitors · inductors and transformers · ground Slightly less basic: amplifier notes · varistors · changing voltage · baluns · frequency generation · Transmission lines · skin effect And some more applied stuff: IO: Input and output pins · wired local IO · wired local-ish IO · ·  Various wireless · 802.11 (WiFi) · cell phone Sensors: General sensor notes, voltage and current sensing · Knobs and dials · Pressure sensing · Temperature sensing · humidity sensing · Light sensing · Movement sensing · Capacitive sensing · Touch screen notes Actuators: General actuator notes, circuit protection · Motors and servos · Solenoids Noise stuff: Stray signals and noise · sound-related noise names · electronic non-coupled noise names · electronic coupled noise · ground loop · strategies to avoid coupled noise · Sampling, reproduction, and transmission distortions Audio and video notes: See avnotes Platform specific: : Microcontroller and computer platforms ·· Arduino and AVR notes · ESP series notes · STM32 series notes · Teensy series notes Less sorted: USB notes · Ground · device voltage and impedance (+ audio-specific) · electricity and humans · Soldering · landline phones · pulse modulation · PLL · Multimeter notes · signal reflection · Project boxes · resource metering · Radio and SDR · vacuum tubes · Unsorted stuff · 'E-fuse' Some stuff I've messed with: Avrusb500v2 · GPS · Hilo GPRS · JY-MCU · DMX · Thermal printer · See also Category:Electronics.

This is largely about soldering in electronics, though some of it applies well to soldering in plumbing as well.

For a wider context, see Soldering, brazing, and welding

Soldering tools

Soldering irons - type and power

✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.

On flux

🛈 Note a lot of this is somewhat more anecdotal (coming from common wisdom, good or bad).
If you have better research - or better anecdote, even - I'd be glad to hear it.

Why flux - mechanics and chemistry

Desoldering

Wick / braid

✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.

Desoldering braid

Wick, a.k.a. desoldering wick, a.k.a. desoldering braid, is useful to absorb the sorts of amount of solder left on a surface.

Used subtly enough, it can also clean up accidental solder bridges, and a few other tricks.

It's basically a braid of stranded copper, which gives it some room to take up solder (a regular braided wire would work similarly, but not as well) the idea being that, when hot enough, you get a capillary-like effect just like regular soldering.

But there are ways to make that easier and harder on yourself -- this wick can be an absolute pain until you figure out some practical details. Look around for advice (videos can be good), and then the kind that sounds like actual experience, not just repeating basics.

Hints:

• Add flux. There is usually a little in the wick, but it never works as well as adding enough

the physics are nontrivial, but the short story is that the braid will absorb/wick a lot better with it.

• it can help to have a little solder on your iron - it transfers heat from iron to wick faster, so you spend less time trying to figure out angles for good contact

note that using the wick will take some it off, so you may even want to re-apply

this also means that spade shapes can work better than pencil

• Press the wick to solder, using your soldering iron on top.

A flat tip works better, delivering heat faster.

Once this heats things enough, the wick's copper is an interesting path for the solder to flow into.

You should not need much pressure at all - enough for good basic contact, but the heat should do the rest.

• consider using a small piece of wick -- and hold it in tweezers

the heat stays more focused, because it's not trying to go into the rest of the roll (it's copper after all)

(if you can have tweezers with no/poor metal contact, even better)

• higher temperatures are often fine - you won't be applying most of that to the board for long

and it's not very different from soldering with that amount of solder anyway

• Factory PCBs tend to use solder that has higher melting temperatures.

If you first add lower-temperature solder to that pool (there are some specialized solders for this), you may have more luck wicking afterwards.

• for fine SMD, you may like to cut the wick's shape into finer points

• some wick is a little better than others.

See also

• Video: How and WHY to Solder Correctly
• http://www.circuitrework.com/guides/7-0.shtml
• http://www.morsex.com/building/atoz.htm
• http://www.kpsec.freeuk.com/solder.htm

• http://www.youtube.com/watch?v=b9FC9fAlfQE

On technique

Learn by mistake

Good solder joints

Read https://learn.adafruit.com/adafruit-guide-excellent-soldering/common-problems