Surface Mount Component Sizes?

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Lo Ryuken

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I'm getting ready to move from the breadboard phase to the prototype phase for my project, and I'd like to use SMCs.

The thing is I don't really know about the sizing stuff. I accidentally bought some 0402 capacitors and I could barely find them.

I'm going to need some transistors, resistors and capacitors. I have some 74HC4051D's already which gives an idea of the component scale. I guess I'd like to choose components that are about the same scale.

As a reference the Teensy components would be too small for my soldering skills.

Any recommendations?
 
Caveat - I use 1.5x magnifying glasses and tweezers to place components. For finer pitches like the LQFP MK20DX I use a 10x scope, or the 1.5x glasses + one of those adjustable lamp + magnifying glass combos.

For discretes, I typically stick with 0603 unless I have a specific need to go smaller. They're fairly tiny but they'll almost always come in tape and you can peel out however many you need onto a white piece of paper and won't lose any.

For transistors, SOT-23X are plentiful and pretty easy to deal with.

For standard-ish chips like a 74hcXXX I usually get them in SOIC; that size is only slightly more difficult than through hole 0.1"

If I've got a board that's got finer pitch chips like the Teensy MCUs, or if I'm going to make a large number of boards, I'll get a stencil and use solder paste and a toaster oven, otherwise I'll just hand solder. Put a tiny blob of solder on one pad, place the component with tweezers, and reheat the pad to tack one leg down, then you can solder the other leg(s) without worry about parts flying off.
 
Binocular magnifying glasses are a must once you stop being a teenager. Plus good lighting. I use a combination of suckers and tweezers depending on the size of the component to move them into place.

Just as I depend on osh park to make my boards, I depend on osh stencil to make stencils. I've standardized around 0805 for resistors, 0603 for decoupling caps, and certain footprints for larger capcitors, depending on their desired capacity. Such standardization helps keep the SKU count down.
 
Well, I use OSH Park for pcbs. You simply cannot beat the quality for the same low price. I have been using 0402 passives for a while now and highly recommend them. They allow smaller board designs but are big enough to solder/desolder with a sharp-tipped iron if necessary.

You need a good pair of tweezers (cheaply available from Amazon) and a good light source with magnification. The easiest way to solder SMT components is with low temperature solder paste and a combo hot plate and hot air gun.

Practice, practice, practice...
 
It comes down to personal preference and board space, but I would recommend starting with 0805. Then move on to 0603. 0603s are still pretty easy to work with and in most cases, you can fit an 0805 part on 0603 pads. Since I use both, sometimes not having the correct value/size combo isn't a tragedy because they can be swapped.
Always order extras, you will lose some sooner or later. Also, be careful with metric/imperial size when ordering.

SMT_sizes%2C_based_on_original_by_Zureks.svg
 
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The thing I like about 0603s is the resistor value is still printed on them; below that they're just little pieces of black.
 
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