[sdiy] LM335 for tempco

[Tim Parkhurst]

On 8/16/05, Peter Grenader <peter at buzzclick-music.com> wrote:
> Phil Gallo turned me on to 3300PPM 1/10w chip resistors as tempcos. You can
> get Panasonics at Digikey in many different values and....they work.  Takes
> a bit of getting used to if you've not dealt with leadless components
> before, but the learning curve is quick.  I built my first 25 VCOs with them
> while I was waiting for a lot of 1/8th watt leaded tempco's to arrive from
> Japan and haven't received a single complaint about their stability.
> 
> Careful use of your super-glue tip and you can actually affix these SMT
> resistors to the underbelly of your expo's with a a pin head sized drop of
> glue and them solder 28 or so gauge solid core wire to them to suffice
> integration to the through hole environment.
> 
> You guys should try it!
> 
> - P
> 
**********************
BTW, this has all been said before, but in the interest of saving time
(and because a search for "PTC Thermistor" doesn't turn up the right
parts), here's the Digi-Key catalog page:
http://dkc3.digikey.com/PDF/T052/1071.pdf
Note that a search for the part number listed below brings up a link
for the wrong catalog page!

and the part number (for the 3300ppm 1.0K) is P1.0KCDCT-ND

These are US$5.52 for ten (min qty). Not a bad deal. In 3300ppm, they
also have 1.8K.

Can anyone suggest the values to change or the math to do if you were
to, for example, sub a 1.0K or 1.8K tempco in a circuit that calls for
a 2.0K? Can you just put two 1.0K in series, or do the tolerances add
to the point where it doesn't work as well as a single 2.0K (assuming
you have a 2.0K tempco)?


Tim (Positive Tim Coefficient) Servo
-- 
"Imagination is more important than knowledge." - Albert Einstein