Through hole resistors - first band up or down? - Page 1
Forum section: electronics / beginners

author: claytonedgeuk
author_rank: Contributor
timestamp: April 08, 2017, 09:44:46 am
content: Is there any convention (or do you follow any convention?) when it comes to lining up through hole resistors for putting into breadboards?If the body of the resistor is upright, would you put the first band at the top or the bottom?It might seem like a trivial thing, but if there is a convention - it'd be great to work along with it than against it!Thanks,Clayton.

author: DimitriP
author_rank: Super Contributor
timestamp: April 08, 2017, 09:56:00 am
content: I don't know if there is a convention.I like the first band on top.

author: Ian.M
author_rank: Super Contributor
timestamp: April 08, 2017, 10:06:57 am
content: Its fairly rare to see vertical resistors in products, (other than some wirewound power resistors in rectangular ceramic packages), as the need for space-saving through-hole layouts vanished when SMD took over. Thus, if there ever was a convention, its long gone. The orientation would have originally been set by the capabilities of the lead forming machine (as there is no reason to design one capable of a 180 deg bend in *BOTH* leads), and the resistor orientation on its bandoleer reel.Its preferable to fit all resistors the same way round on any axis - nothing looks much messier than two adjacent resistors of the same size with band 1 at opposite ends.As Dimitri just pointed out, top down, rear to front and left to right make sense as it matches the digit order you would use writing the value in scientific notation.

author: pmcouto
author_rank: Unknown
timestamp: April 08, 2017, 10:30:17 am
content: Quote from: Ian.M on April 08, 2017, 10:06:57 am+1

author: Hideki
author_rank: Frequent Contributor
timestamp: April 08, 2017, 10:37:01 am
content: For a commercial product, maybe there are someone who cares, but for breadboards? No, there isn't and probably never will be any convention.The legs of the resistor are stuck into whatever two holes are needed for the circuit, with the body of the resistor floating somewhere up above the breadboard. Only in very rare occasions will a resistor have a leg shortened and placed the way you have drawn. In those rare occasions, any thoughts on what way to place it may only be given by those who value tidyness above anything else.

author: Brumby
author_rank: Unknown
timestamp: April 08, 2017, 01:53:48 pm
content: Quote from: Hideki on April 08, 2017, 10:37:01 amFor a breadboard, I'm more interested in getting the circuit to perform as expected. I don't pay any attention to the orientation. The concern is getting the right component into the right holes.For a final product, even if it's a home spun board,thenI will follow a consistent orientation for readability.

author: mariush
author_rank: Super Contributor
timestamp: April 08, 2017, 02:23:41 pm
content: It doesn't matter. I'd probably arrange them with the color strips closer to the pcb.I used to place resistors like this, vertically, but only because I was somewhat afraid of moving to surface mount resistors.Thing is you can buy easily 0805 and 1206 resistors and they can be so easily soldered to a pcb if you have a good soldering iron, it's not worth using leaded resistors unless you do prototypes. Both can sit nicely on top of two holes 0.1" or 0.2" apart.Even then with one sided through hole pcbs you can just get some solid gauge wire (like awg24 solid core wire from an ethernet cable, just make sure it's not a cca type one), solder wires in the pcb holes and then solder ceramic capacitors on the other side.And you have the benefit of being able to stack these chips resistors if you need some weird resistance value.

author: Hideki
author_rank: Frequent Contributor
timestamp: April 08, 2017, 04:49:39 pm
content: Quote from: mariush on April 08, 2017, 02:23:41 pmWell, the question was about resistors on abreadboard, not on a PCB. Although... maybe the OP really meant a PCB, since that's what the attached image shows (perhaps even some kind of stripboard). Who knows

author: SeanB
author_rank: Super Contributor
timestamp: April 08, 2017, 05:02:46 pm
content: Breadboard it is easier to decide on an orientation of the first band, and stick to it. Just makes placing easier and eases troubleshooting to be able to see where the 22k resistor is on the board. On a PCB old designs with vertically oriented resistors used generally a resistor designed for vertical mounting, which had a lead on the one side that was coated with lacquer for the body length on it, and this always meant the tolerance band was closest to the board when inserted. doing this on a breadboard would probably be just as good but would mean you cut the leads and thus render it less usable in the future, unless you use it on a board like that again.

author: james_s
author_rank: Super Contributor
timestamp: April 08, 2017, 05:03:05 pm
content: I guess it depends on how severe your OCD is. On a breadboard I've never bothered to install resistors vertically anyway.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: April 08, 2017, 09:31:23 pm
content: But won't the ohms fall out if you get them upside down?And how the heck do you manage to mount those tiny SM resistors vertically, anyway?

author: Ian.M
author_rank: Super Contributor
timestamp: April 08, 2017, 10:26:21 pm
content: Quote from: SeanB on April 08, 2017, 05:02:46 pmI'd forgotten about those, let-alone which way round the bands were.Quote from: alsetalokin4017 on April 08, 2017, 09:31:23 pmThey've got this wonderful feature called 'Toombstoning' that can automatically orient them vertically.

author: Nusa
author_rank: Super Contributor
timestamp: April 08, 2017, 10:49:40 pm
content: It's always fun to use the 3rd dimension:

author: pelule
author_rank: Frequent Contributor
timestamp: April 08, 2017, 10:57:34 pm
content: In the "old" times, when through hole mounting was a standard, the rule was, to put all in the same orientation to make readability easier.For upright mounted resisitors this was finally defined by operator of the bend-crimp-cut machine. The resistor are delivered in belts without a mmarked side (in oposite to diodes or other polarized parts). Thus the operator of the machine finally defined it by the way, he feed the machine with.Note: upright mounted resistors should crimped for two main reasons- to redcue the force of the leed to the part- easier pick & placing/PeLuLe

author: DimitriP
author_rank: Super Contributor
timestamp: April 09, 2017, 12:51:41 am
content: Quotenot to mention parts with crimped leads stay put and don't fall out when you turn the board upside down to solder them (well..ok , I mentioned it)

author: SeanB
author_rank: Super Contributor
timestamp: April 09, 2017, 04:46:57 pm
content: In Cordwood boards you always put the resistors with the top board having the first digit band, and the bottom board the tolerance band. Of course there is no auto inserting machine that can actually make these boards, so they were all hand assembled, had the leads cut to length and then bent over before soldering. There at least you could wave solder in a jig, and then check the board for rotated leads and correct them before the second pass.Now, do you bus the point to point wiring on a breadboard, or just use a mostly straight line approach from point to point.