winterhunter
New Member
Hi everyone,
I need to be able to sense the room temperature quite accurately (+/- 0,1°C for a temperature range between 15 and 25°C - I should be nevertheless able to measure from -10°C to +45°C) using a KTY 10-62 silicon temperature sensor.
The measurement current should be around 1 mA, and I will use a 10-bit A/D converter (PIC 16F877A).
For a ~1mA current, the voltage drop at 15 °C will be 1mA x 1846 Ohm=1,846V and 2 V at 25°C. This leaves us a deltaV of 164mV.
If the 0-5V is represented by 10 bit, I get around 5mV per division, which in turn leads to ~33 divisions between 15 and 25°C --> the precision is then +/- 0,3 °C
How can I improve things to "expand" the full range (-10°C-->1496Ohm to +45°C-->2331 Ohm) to the 0-5V acquisition range of the ADC?
Thanks a lot!
I need to be able to sense the room temperature quite accurately (+/- 0,1°C for a temperature range between 15 and 25°C - I should be nevertheless able to measure from -10°C to +45°C) using a KTY 10-62 silicon temperature sensor.
The measurement current should be around 1 mA, and I will use a 10-bit A/D converter (PIC 16F877A).
For a ~1mA current, the voltage drop at 15 °C will be 1mA x 1846 Ohm=1,846V and 2 V at 25°C. This leaves us a deltaV of 164mV.
If the 0-5V is represented by 10 bit, I get around 5mV per division, which in turn leads to ~33 divisions between 15 and 25°C --> the precision is then +/- 0,3 °C
How can I improve things to "expand" the full range (-10°C-->1496Ohm to +45°C-->2331 Ohm) to the 0-5V acquisition range of the ADC?
Thanks a lot!