I am looking for some data sheets or diagrams to tell me how to set my comparitor LM393 to enable the use of this sensor down to the 0 degrees C to -10 C. Im using the Jaycar Tempmaster MK2 kit which is based on the Silicon chip article in Feb 2009
Anybody have any sites ?
The basic range of the LM335 is -40C thru +100C at 10mV/C.
So at -10C you will get 30 * 0.01= 0.3VΔ and at 0C 0.4VΔ.
NOTE: the offset is from absolute zero -273C, these values are relative from -40C.
Are you asking for a LM393 circuit that switches at -10C and 0C, ie: a window comparator.??
Do you follow OK.?
Err I don't think.. you got this right, it reads 2.73v at 0C and 2.93v at say 20C so at -10 C it would be 2.63v .I don't know what you mean by the Delta sign .....0.3v change? 0.4v change?
Eric is this supposed to be the original circuit or is it something else ?
In both the circuits you have the comparitor + feed coming off after the 3.3k resistor. This is not the case ,it comes off before
What is the significance of the time graph?
I can see the voltages at which the comparitor switches off and on but what do the Ms mean.
I am trying to make sense of this -I know its probably me ! I have downloaded LTSpice IV which is freeware and am trying to make it work.
Can I copy this .gif file somehow or can you post the .asc file so I may import it ?
But now from here how do I get it to show me when it switches on and off?
I can measure voltages etc and they show on the graph but can I get a meter circuit so I can attach a meter at various points and watch the voltage change as I change values?