Author Topic: Help picking capacitor and resistor footprints?  (Read 2431 times)

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Online YurkshireLad

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Help picking capacitor and resistor footprints?
« on: November 09, 2021, 03:46:52 pm »
I'm an absolute beginner with KiCad, and I'm trying to create simple project for an op amp circuit that I have working. I'd like to build it up in KiCad so I always have an up to date diagram.

For snits and giggles, I thought I'd add footprints and view the 3d PCB. However, I'm overwhelmed and confused by the number of capacitors to choose from. I want to pick THT capacitors, but there are axial, radial, disc etc. Which should I use?

The same goes for resistors. Thanks!
 

Online TimFox

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Re: Help picking capacitor and resistor footprints?
« Reply #1 on: November 09, 2021, 04:35:25 pm »
The question for PCB footprints is self-answering:  "It depends".
For leaded resistors, you could use the pattern appropriate for 1/2 W film resistors, or for the military RN60 size, since smaller bodies can easily fit into the axial pattern.
Similarly, for leaded capacitors you could settle on an axial package that is large enough for various parts, although modern leaded capacitors trend towards radial, where the lead spacing is more important to avoid ugliness.
Discrete resistors and capacitors for schematic capture are easy:  the only question is polarized or not.
 
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Online Doctorandus_P

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Re: Help picking capacitor and resistor footprints?
« Reply #2 on: November 10, 2021, 12:55:30 pm »
Start with buying a few assortment boxes for resistors / ceramic capacitors, electrolytic capacitors, transistors.

Then just use the sizes in KiCad that you have available.

I like working with THT parts on breadboards, but if you design a PCB, working with SMT is just a lot easier.
* You don't have to bend pins.
* You don't have to cut the pins to size.
* You don't have to turn the pcb around for soldering.
    * Parts don't fall off.
    * No confusion of working with mirror images.
* You don't have to drill holes in the PCB (for home etching).
* You can put parts on two sides of the PCB.

For starters I recommend to use 0805 (imperial) seize for SMT resistors / capacitors.
Do make sure you've got a decent set of tweezers.
Most people can still easily solder 0805 without more equipment. If you want to go smaller later, then a decent stereo microscope would be one of the first upgrades.

And in these days of IC shortages.
Order your IC's and make sure you get them before you design the PCB.
Stock can easily dry up in the time that you're designing the PCB or ordering it.
 
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Online YurkshireLad

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Re: Help picking capacitor and resistor footprints?
« Reply #3 on: November 10, 2021, 12:57:09 pm »
Thanks. I only just started trying to solder THT so SMD is a bit of a stretch for me.  :)
 


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