Electronics project notes/Common terms, useful basics, soldering

⚠ 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 notes: See avnotes Platform specific Arduino and AVR notes · (Ethernet) Microcontroller and computer platforms ··· ESP series notes · STM32 series notes Less sorted: Ground · device voltage and impedance (+ audio-specific) · electricity and humans · power supply considerations · Common terms, useful basics, soldering · landline phones · pulse modulation · signal reflection · Project boxes · resource metering · SDR · PLL · vacuum tubes · Multimeter notes Unsorted stuff Some stuff I've messed with: Avrusb500v2 · GPS · Hilo GPRS · JY-MCU · DMX · Thermal printer · See also Category:Electronics.

Boards and wiring

PCBs

Printed circuit boards (PCBs) refer to ready-made boards.

PCBs may be two-sided, or have three (or more) layers, where sandwiched layers usually purely have copper traces that allow more complex wiring than a double-sided board could give, with almost no added space.

Such PCBs are likelier to use SMT components, partly just because holes through everything are a design problem.

You can etch your own single-sided board fairly easily, and double-sided if you're adept. For more complex designs, or batches of a few dozen or more, it may become worth it to have them produced for you, though this is not particularly economical for hobbyists.

There are some PCBs that are useful to prototyping - such as pitch conversion boards.

Breadboard, protoboard, and such

Breadboard and Protoboard can refer to most boards mentioned below - solderless breadboards, raster/strip/perfboards, and more.

These are typically THT style and have 2.54mm (0.1") pitch, which means SIP, DIP and other packages, and wires up to roughly AWG 22, are also comfortable enough to use.

Solderless breadboard

Solderless breadboards, a.k.a. plugboards, are plastic boards with rows/columns of friction locked holes, very usually at 2.54mm (0.1") pitch. The arrangement s usually to connect columns, with one or two rows above and below (most often used for Vcc+Gnd)

These have a little bit more capacitance than PCBs, stripboards, and such, so avoid these for high-frequency applications.

People regularly use some solid-core wires to plug around these things (even pre-cut, partly just because shops tend to sell them), and it can look like a rather neat variant of your drawn circuit.

Size is referred to by the amount of connection points. Some common sizes include:

170 point is the cute tiny sort

270 point

400 point seems to be the average and common one

830 point is basically a long variant of 400 (16x5cm)

1280 point

1660 is basically two 830s under each other (16x10cm)

Back of a used stripboard, with most lanes cut into two or more parts (and consistently too much solder used)

Stripboard (UK: Veroboard) refers to holed boards with all holes for a row (or short groups, e.g. tripad) connected using copper strips. You can cut through these strips as you need to. Whenever you can use the copper strips, this can save a bunch of wiring and mess, particularly on simpler circuits.

Maximum current varies, but never count on moving more than half an amp (the copper width is decent, but at holes it's at most half that, so current that has to go past those holes is problematic). You can cheat a little with solder, or perhaps using multiple lanes, but soldering in an appropriate-gauge wire is often a better and easier solution.

Perfboard with verowire and plastic wiring channels

Perfboard / raster boards refers either to things with holes but no copper, (probably) more commonly, to boards with individual islands of copper, mostly for ease of soldering.

Exist in a bunch of varying looks and qualities.

Adjacent islands can be connected via channels of solder, longer-distance connections can be made with wires - a wiring pen can be handy if you have one.

Can be convenient when the circuit is somewhat complex, when stripboard would mean a lot of cutting and triboard isn't so convenient either.

Wiring pens/wiring pencils , wire-wrap, and the associated wire (UK: Verowire) are often used as an easy way to add individual between soldered points, particularly on perfboard.

Wire (usually copper with a thin plastic coating to insulate against other such wires) is often quite thin overall, and only for low currents (logic paths - fine for most 12-and-fewer-volts logic).

With a steady hand and some non-conducting adhesive tape (there are some specialists tapes) this can even be used for small-pitch / SMT components - which can be nice on protoboards.

See also:

• http://en.wikipedia.org/wiki/Breadboard
• http://en.wikipedia.org/wiki/Stripboard
• http://en.wikipedia.org/wiki/Perfboard

• http://en.wikipedia.org/wiki/Wiring_pencil
• http://elm-chan.org/docs/wire/wiring_e.html
• http://info.ee.surrey.ac.uk/Workshop/advice/grotwire/usingPen.html
• http://www.instructables.com/id/How-to-Prototype-Without-Using-Printed-Circuit-Boa/

Circuit drawing, circuit simulation

✎ 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.

• Eagle [1]

• Fritzing [2]

win, lin, osx

• LibrePCB [3]

win, lin, osx

• Micro-Cap 12

win

• KiCAD [4]

win, lin, osx

• LTspice

..and many others (TODO)

See also:

• http://en.wikipedia.org/wiki/Comparison_of_Free_EDA_software

Fixing in place

✎ 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.

There's always hot glue., though it doesn't hold well on every surface.

If you want boards to be solidly in place, not contact anything near it, but still be removable, the simplest solution may be to use one of:

• spacer nuts; use screws to actually fix

• plastic spring-locking standoff spacers

• PCB edge holder

basically thin slots you slide the PCB into.

e.g. a few plastic clips

some project boxes have these along their length (for a single breadboard size)

Soldering

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 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.

Soldering 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 for the solder (a regular braided wire wouldn't work as well) and the idea is that when hot enough you get a capilarry-like effect.

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

Once this heats things enough, there's a capillary-like effect that makes most of the solder flows into the wick.

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

You will probably have a much easier time with enough flux in the braid - thy physics are nontrivial, but the short story is that the braid will absorb/wick a lot better with it.

Dipping it in liquid flux just before use is perhaps the easiest - which isn't the form you necessarily have around.

Using braid also seems to work a little better when your soldering tip is flat, delivering heat faster. It also means that if you are holding the wick in place, you're less likely to burn your fingers.

If you pull open the wick it may absorb more, but only a little, and only if it was really packed before.

2mm-wide wick seems fairly general-purpose.

Wider can be nice for removing larger blobs.

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

Good solder joints

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

Boxes, safety, weatherproofing

Some safety considerations

• Chassis grounding
  • done for fire safety, human-shock safety,

• Pull resistant cable clamps
  • Particularly on power cables, but useful for anything that avoids pulling on something weak via something stronger
  • may also be water resistant

Splash-proof / waterproof box, and moisture resitance

Enclosure

Tupperware is an easy and cheap splash-proof option - and often seals fairly well, to be decent against things like dew and rain with a minimal consideration, and perhaps a little hot glue to seal the holes you make for wires.

For serious projects you can buy nice-looking boxes and may may be IP-rated, and may react to heat better than, say, tupperware.

Connectors

Usually most relevant is how condensation may affect closeby conductors.

Conformal coating, potting

✎ 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.

Conformal coating refers to materials that don't conduct electricitly, that protect against forms of moisture (including condensation), fungus, corrosion (from salt or other), dust, heat and such.

Frequently acrylic, urethane, silicone, epoxy, or paraxylene, each of which have some specific upsides.

Usually applied as a thin layer (sprayed, brushed, or dipped). Sometimes potting[5] is used instead (note: potting has more direct thermal implications).

Keywords that might be handy while searching:

• electronic coating
• protective coating
• conformal coating
• (weather) protection/protective lacquer
• Various brands / product names - Kontakt chemie, Humiseal, etc.

Some common coatings:

• acrylic

easy to apply

good against moisture and such, not so good against abrasion, some chemicals, natural solvents

• silicone

lower dielectric value than most others

can stand more heat than some others

arguably easier to repair than various others

• (poly)urethane

resists many chemicals well

not the healthiest to work with

• epoxy

hard

easy to apply (but warm)

hard to remove

resists many chemicals well

not the healthiest to work with

• paraxylene

See also:

• http://en.wikipedia.org/wiki/Conformal_coating