Snapistor - Anyone ?

[goaty]

Just got this curious Resistors off eBay, maby worth sending to the Mailbag.

[daqq]

Well, it worked. This is similar, although less violent:

https://www.element14.com/community/videos/18448/l/precision-centers-express-delivery-of-custom-resistor-values-demo-video-vfr

Trimming/setting resistors for custom values by hand.

[Ian.M]

They are mentioned in the PARIS Components SHOW (Salon International des Composants Electroniques 1978) report by David Gibson

...
One device causing raised eyebrows was the "Snapistor".  This is a thick film resistor network on a ceramic substrate.  Pre-scribed lines on the back of the substrate divide it into ten parts.  Each part can be snapped off, one by one, and each snap increases the remaining resistance by 20 %.  This gives a five-fold increase in resistance when all nine parts have been broken off.  Applications suggested are; to set the gain of a transistor stage, or to set up the voltage of a voltage regulator.  Here, one could use one Snapistor for coarse adjustment, and another for fine setting.  Various ranges of resistance values were offered.  These included ; 100Ω to 520Ω, 10kΩ to 52kΩ, 33kΩ to 520Ω, and 100kΩ to 520kΩ.  The resistance values are +20%, TCR +100 ppm/°C and operating temperature range -40°C to +125°C.  Power handling capability depends on how much snapping you've done.  If they are unsnapped (i.e. all sections are in circuit) then the power capability is 250mW; with just a lonely one segment, power is 50mW.  Maximum voltage is 100V.
...

[thm_w]

That broken ceramic could be very sharp and nasty... if you've ever cracked open a ceramic fuse you'll know.

[AVGresponding]

That broken ceramic could be very sharp and nasty... if you've ever cracked open a ceramic fuse you'll know.

Given the conductive properties of blood, this could help with fine value trimming...

[mzzj]

Damn, now I finally have name for those!

I remember reading about them 20-30 years ago in some book or trade magazine but wasn't able to find any reference to them when I was looking at it few years ago. I thought that I must have been dreaming.

[niconiconi]

This gives a five-fold increase in resistance when all nine parts have been broken off.  Applications suggested are; to set the gain of a transistor stage, or to set up the voltage of a voltage regulator.

So it's basically a special resistor designed for easy trimming? It reminds me of the 1979 National Semiconductor application note on cutting parallel/series resistor arrays as a cheap (and safer...) alternative to potentiometers for LDO voltage trimming. 

https://www.ti.com/lit/an/snva582/snva582.pdf