Farnell Temperature Sensing resistors

[Keith Winstanley]

I had so many differing opinions about these 'Tempcos', someone 
pointed me towards them as a source of tempcos, others have told me 
they are thermistors, never the less I though I would have a look at 
one.

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Catalogue details:

Farnell April '99
Electronic Components
Page 1564
Temperature Sensing Resistors
Meggitt Electronic Components

Order Code: 732-278

PTC Axial Lead
*       Resistance value increases linearly with temperature rise
*       Applications include temperature compensation in sensitive      
        electronic circuits
*       Available in 0.25W and 0.17W

Heat dissipation                0.25W = 9mW/degC 0.17W = 5mW/degC
Time Constant           0.25W = 7.5sec, 0.17W = 3.0sec
Std Resistance @ 25 degC        1K, 5K, 10K +-5%
Temperature Coefficient         0.3%/degC @ 25degC (3000ppm/degC) +-10%
Resistance Ratio                R25degC/R125degC = 1.37
Operating Temp Range    -40degC to +125degC
High Temp Stability     1000 hours @ 125degC, 0.5% deltaR
Insulation Resistance   >10G Ohms
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Well, I heated it under a lamp and resistance went up!
Not really surprised.
I suppose the only way for me to be sure if I can use one is to build 
one of Tom G's oscillators and compare it with a chip heater.

Unless someone has already tried one??
Any opinions?


regards.....


Keith Winstanley
http://home.freeuk.net/lowpass