Honey, I Shrunk the Resistors

[guitician]

Interesting stuff! I recently bought a Vishay 1 watt metal film resistor and it was 6x2mm! I had thought it was a mis-pull, but the data sheet comfirmed it.

http://www.mouser.com/catalog/specsheets/pr010203.pdf

Another thing to think about is the melting point of the solder. I checked and it looks like Sn63 types melt at 183C and 95% lead at 307C. Using 95% lead could help keep them hot ones in place.

[loudthud]

I ran into this subject when I switched companies in the late 80s. At the first company, RN55s (a military spec) were called 1/8W. At the next company they were called 1/4W. Turns out both were right. The spec sheet said 1/8W @ 125C, 1/4W @ 85C. They were almost always 100ppm. Occasionally you could find 50ppm parts. But when the move came to surface mount, it was hard to find any 1% parts that were 100ppm. IIFC 250ppm was the norm.

[bob p]

Here's the photo that seems to have disappeared from the first post:



All 3 groups of resistors are 500 mW, 1% metal film resistors that came from different manufacturers.

LEFT Vishay/BC Components, SFR16S0 series. As I recall they're manufactured in Brazil and Thailand. They're diminutive in size. 500 mW power rating. here's the data sheet:

http://www.vishay.com/docs/28722/sfr16s25.pdf

MIDDLE Wellwyn, made in the UK. They are about the size of what I think of when I think of a 1/2 watt metal film resistor.

RIGHT MultiComp, made in China. They are HUGE, and oversized for what I think of as a 500 mW resistors, and noisy.

[Steve A.]

Here's the photo that seems to have disappeared from the first post:

An email was sent to me requesting that your fresh attachment be added to your original post and after much deliberation that wish was granted. Just kidding... no deliberation was required (I do this for anybody who requests it.)

Note to all: Many attachments were lost in a computer malfunction several years ago and are gone for good. But if they can be reuploaded in a new post they can be easily attached to the original post — just send me a PM directing me to the thread. (If you only have an external link to the file send me that and I'll try to download it and attach it the original post, or at least add the new link to it.)

BTW if anyone needs an older post edited or deleted just let me know and it will be done.I don't get email notification of PM's sent to me so for faster service you can send me an email through the site*** telling me to check my messages. (I'd post my email address here but anything posted at MEF shows up on Google within hours!)

Steve A.

P.S. I had always thought that PM stood for "Private Message" but at Facebook I learned otherwise... a topic I *only* mentioned in a PM (not a public post) started appearing in my personalized ad feed. Huh?!? And at Kaiser Permanente I learned the hard way that the messages I sent in confidence to my doctors could be read by practically any member of their staff... Ouch! At many sites PM stands for Personal Message, not Private Message.

Disclaimer: I have only read PM's here personally addressed to me (I respect privacy more than practically anything else — like flags, anthems, presidents, bosses, no trespassing signs, deities and demigods. My bumper stick would read "Question Authority"...)

*** As shown in the following pictures click on my name (Fig. 1) to see a list of options (Fig. 2):


Fig. 1

-=÷=◇=÷=○=÷=◇=÷=-


Fig. 2

-=÷=◇=÷=○=÷=◇=÷=-