Newbie PCB SMT question

Thread Starter

JohnnyKnox

Joined Sep 4, 2022
11
Hello all

i couldn’t find a topic listed that covered this. Very generic question. Do most smt type circuit boards also have a few spots For through hole components. I see holes in them in tutorial i watch but see no reason given. I’m contemplating moving to smt construction but wonder if the holes are for components too big to be made into smt versions.
Thanks
 

WBahn

Joined Mar 31, 2012
27,392
Every PCB is different. You put pads where you need pads and you put holes where you need holes. If you don't need any holes, you usually don't put any holes. Holes that are there could be for any number of reasons. They might be for thru-hole components, or they might be for mounting, or they might be to put wires through, or they might be for alignment, or they might be for air flow, or they might be for any number of different things.
 

Thread Starter

JohnnyKnox

Joined Sep 4, 2022
11
Every PCB is different. You put pads where you need pads and you put holes where you need holes. If you don't need any holes, you usually don't put any holes. Holes that are there could be for any number of reasons. They might be for thru-hole components, or they might be for mounting, or they might be to put wires through, or they might be for alignment, or they might be for air flow, or they might be for any number of different things.
Thank you for your prompt response. Makes sense.
 

dl324

Joined Mar 30, 2015
15,112
I’m contemplating moving to smt construction but wonder if the holes are for components too big to be made into smt versions.
Sometimes I put through hole and surface mount footprints for the same component to give more flexibility.

From a breadboarding and rework perspective, I prefer through hole parts.
 

MrSalts

Joined Apr 2, 2020
2,354
Large resistors (high wattage) are still likely through-hole or even chassis mount. Some people like to use through-hole for Large electrolytic capacitors and large chokes / inductors. These larger/heavier pieces, when mounted as SMD, can rip the copper pads off of the PCB. The through hole option gives more strength and, therefore, requires less potting/adhesive to hole them in place. An important consideration for things that get moved frequently or possibly dropped, I recently opened a JBL portable bluetooth speaker (a large one) and it used through-hole capacitors and for connectors for the large lithium battery pack.
 
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