AMICUS18-COMPANION-SHIELD AMICUS, AMICUS18-COMPANION-SHIELD Datasheet - Page 37

• Manufacturer Part Number: AMICUS18-COMPANION-SHIELD
• Description: Amicus18 Companion Shield
• Manufacturer: AMICUS

Specifications of AMICUS18-COMPANION-SHIELD

• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC18
• Features: USB Interface, In Circuit Serial Programming Interface
• Kit Contents: Board
• Silicon Family Name: PIC
• Silicon Core Number: PIC18F25K20
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: PIC18F25K20 Microcontroller

Amicus18 Companion Shield
Temperature Sensor
One of the simplest, and least expensive, temperature sensors is a thermistor. This is a special type of
resistor that alters it’s resistance based upon it’s temperature. There are generally two types of thermis-
tor; an NTC type (Negative Temparature Coefficient), whose resistance drops as the temparature in-
creases, and a PTC type (Positive Temparature Coefficient), whose resistance increases as the tempara-
ture increases. For this demonstration, we’ll use an NTC thermistor.
Just like there fixed resistance cousins, thermistors come in different packages and resistance-per-
temperature values. These range anywhere from a few hundred Ohms to tens of thousands of Ohms.
The device used in this demonstration is a bead thermistor with a resistance of 10KΩ at a temperature
o
centigrade, but any thermistor will do with a few program code changes.
of 25
A thermistor layout is shown below:
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Crownhill AssociatesLimited 2009 - All Rights Reserved
Version 1.0
06-10-2009