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Octopart Pocket Electronics Reference PCB

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Re: Octopart Pocket Electronics Reference PCB

#11

It's fun, but I'm not sure what it's for as I can look up these things on the internets if I forget. Is this just an executive engineer gadget?

It would be a good thing for my students to have in their kits. I try to get them to make something similar for SMT footprints every year (to print out on paper) with varying amounts of success. It is easy to get confused on different size designations (QFP, TQFP especially), and there is not a lot of utility in making people memorize stuff like this.

Re: Octopart Pocket Electronics Reference PCB

#12
post #8

Like the SM footprints, but I'm not sure I see the point of the resistor color code chart these days (If I do spec a through hole resistor, 99% of the time it'll be a 1%).

Not sure I understand - Vishay[1] MRS25 resistors are 1% and use a colour code. ( http://www.vishay.com/docs/28724/mrs16m25.pdf ) They're generally pretty nice as resistors go. Do you spec better than that? [1] I used these when they were Philips, which shows how long it is since I was doing this stuff.

Most SMT resistors use a number code. Also, colorblind people.

Re: Octopart Pocket Electronics Reference PCB

#13
post #8

Like the SM footprints, but I'm not sure I see the point of the resistor color code chart these days (If I do spec a through hole resistor, 99% of the time it'll be a 1%).

Not sure I understand - Vishay[1] MRS25 resistors are 1% and use a colour code. ( http://www.vishay.com/docs/28724/mrs16m25.pdf ) They're generally pretty nice as resistors go. Do you spec better than that? [1] I used these when they were Philips, which shows how long it is since I was doing this stuff.

The 1% series has an extra value band, which throws off their multiplier. Example: 1k 5% is brown black red (gold), but 1k 1% is brown black black brown (brown).

We do use a few 0.1% values in some cal equipment--about $1 each!

Re: Octopart Pocket Electronics Reference PCB

#14
Hmmm, meybe i'm getting this wrong, but... Isn't a color code too basic to be in a card in your pocket?

I mean, c'mon, i haven't used color codes since High School about 17 years ago and i still remember how to decode them. It's not that hard.

i feel that consulting a table is more time consuming that knowing how to decode it... Usually while working with prototyping you end up with lots of resistors, and i can't see someone checking each one at the time against a table to reveal it's value...

But maybe i'm getting it all wrong, someone?

Re: Octopart Pocket Electronics Reference PCB

#15

I prefer using a multi-meter. That might be something to do with being colour-blind though.

That's a pain-in-the-butt way to find the one resistor you need in a pile of fifty. Even though you are color-blind, that's just red and green, so you too can say to yourself "blue, blue, I need two blue stripes..."

Re: Octopart Pocket Electronics Reference PCB

#16

Hmmm, meybe i'm getting this wrong, but... Isn't a color code too basic to be in a card in your pocket? I mean, c'mon, i haven't used color codes since High School about 17 years ago and i still remember how to decode them. It's not that hard. i feel that consulting a table is more time consuming that knowing how to decode it... Usually while working with prototyping you end up with lots of resistors, and i can't see…

[deleted]

Re: Octopart Pocket Electronics Reference PCB

#17

It's fun, but I'm not sure what it's for as I can look up these things on the internets if I forget. Is this just an executive engineer gadget?

It would be a good thing for my students to have in their kits. I try to get them to make something similar for SMT footprints every year (to print out on paper) with varying amounts of success. It is easy to get confused on different size designations (QFP, TQFP especially), and there is not a lot of utility in making people memorize stuff like this.

Package types are not size designations. Pin count & pitch matter more than QFP vs. TQFP, and the dimensions of one manufacturer's TQFP can easily be different from an others, so the datasheet is key.

Re: Octopart Pocket Electronics Reference PCB

#19

Hmmm, meybe i'm getting this wrong, but... Isn't a color code too basic to be in a card in your pocket? I mean, c'mon, i haven't used color codes since High School about 17 years ago and i still remember how to decode them. It's not that hard. i feel that consulting a table is more time consuming that knowing how to decode it... Usually while working with prototyping you end up with lots of resistors, and i can't see…

If you're breadboarding a lot, or manually stuffing printed circuit boards, or otherwise doing manual assembly in some way, you quickly learn to read most common ranges of values on sight. Maybe some people like to keep a reminder around for when you encounter weird values, or when troubleshooting.

Re: Octopart Pocket Electronics Reference PCB

#20

I prefer using a multi-meter. That might be something to do with being colour-blind though.

That's a pain-in-the-butt way to find the one resistor you need in a pile of fifty. Even though you are color-blind, that's just red and green, so you too can say to yourself "blue, blue, I need two blue stripes..."

That's a weird mis-characterisation of what it means to be colourblind. It's one of the discriminations that's still legal in England - electronics companies are allowed to not employ people with colourblindness because of the lack of suitable 'reasonable adjustments' and the need to have colour vision for a lot of electronic stuff.

Also, any resistors not in a pcb should be in a nice drawer with a neat label; any resistor in a circuit could give misleading values when multimetered because it's in a circuit.

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