Electronics project notes/Common terms, useful basics, soldering

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This is for beginners and very much by a beginner.

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 · Ground · batteries · resistors · changing voltage · transistors · fuses · diodes · varistors · capacitors · inductors · transformers · baluns · amplifier notes · frequency generation · skin effect


And some more applied stuff:

IO: Input and output pins · wired local IO · wired local-ish IO · · · · Shorter-range wireless (IR, ISM RF) · RFID and NFC · bluetooth · 802.15 (including zigbee) · 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

Some stuff I've messed with: Avrusb500v2 · GPS · Hilo GPRS · JY-MCU · DMX · Thermal printer ·


Audio notes: microphones · device voltage and impedance, audio and otherwise · amps and speakers · basic audio hacks · digital audio · noise reduction · multichannel and surround ·


Less sorted: Common terms, useful basics, soldering · Arduino and AVR notes · ESP series notes · PLL · signal reflection · pulse modulation · electricity and humans · resource metering · Microcontroller and computer platforms · SDR · Unsorted stuff

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, but this should only bother a few 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).

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

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:

Circuit drawing, circuit simulation

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)
win, lin, osx
win, lin, osx
  • Micro-Cap 12
win
win, lin, osx
  • LTspice


..and many others (TODO)


See also:

Fixing in place

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

There's always hot glue. (Though it doesn't hold 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:

  • 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

Soldering irons - type and power

On temperature

Tip selection

On buying solder

On flux

Some related physics and chemistry

Solder flows with heat

More on flux

More on tips

SMD and tips

Reflow soldering

Unsorted hints

Further tools

Desoldering

Wick / braid

Wick, a.k.a. desoldering wick, a.k.a. desoldering braid, is useful to absorb most solder into what is basically thin stranded copper.

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

Press the wick to solder, using your soldering iron on top. Once warm 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 - the heat should be enough.


You will probably have an easier time with some flux inbetween, or in the braid. You can get braid with flux, but adding flux just before use work just as well and probably lasts longer.

A larger (and flatter) soldering tip cam be handy to deliver the heat faster and be done faster, so that you don't burn your fingers on the wick.

If you open the wick a bit you may get a little more absorbed


2mm-wide wick is fairly general-purpose. Wider can be useful for removing larger blobs.


On reflow soldering

Reflow for fixing

See also

On technique

Good solder joints

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

On (not) damaging components

Typical components
Battery packs

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 — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

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:



Unsorted