minor update

git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@1103 7894878c-1315-0410-8ee3-d5d059ff63e0

doc/temperature-sensors

@@ -1,5 +1,5 @@
-Termistor and Transistors as Temperature Sensors
-------------------------------------------------
+Thermistors and Transistors as Temperature Sensors
+--------------------------------------------------
 Temperature measuring chips that use external sensors
 generally are designed to use either thermistors or
 transistors. Check the driver documentation in doc/chips
@@ -19,8 +19,9 @@ Thermistors
  most thermistor companies don't have much on their web sites but
  Thermometrics has a comprehensive guide)
 
-NTC (negative temperature coefficient) thermistors
-have a parameter B (beta), units are K (kelvin).
+NTC (negative temperature coefficient) thermistors decrease their
+resistance with an increase in temperature.
+They commonly have a parameter B (beta), units are K (kelvin).
 B is the "material constant" of the thermistor and
 is a measure of the change of resistance with respect to temperature.
 It is the slope of the line graphing (ln R) vs. (1/T).
@@ -46,6 +47,9 @@ Winbond W83782D data sheet the change is 3.8%.
 For thermistors, resistance (= voltage for a constant current)
 is exponentially related to temperature.
 
+PTC (positive temperature coefficient) thermistors increase
+in resistance with an increase in temperature. They are not
+commonly used for accurate temperature sensing.
 
 
 Transistors / Diodes
@@ -97,3 +101,7 @@ thermistors. Generally, sensor chips are designed to be connected
 to one or the other and cannot be configured. The Winbond
 W83782D/W83783S chips are exceptions, they can be
 configured for either.
+
+
+------------------
+Copyright (c) 1999, 2001 Mark D. Studebaker <mdsxyz123@yahoo.com>