"Jason S" bravely wrote to "All" (01 Dec 05 21:12:24) --- on the heady topic of "Ambient temperature sensing"
JS> From: "Jason S" JS> Xref: core-easynews JS> sci.electronics.repair:350096
JS> Hi,
JS> I'm looking for a circuit that will represent temperature ranges up to JS> 60 degrees (celcius) using at least 3 LED's or transistors as the JS> outputs for each range, but I DO NOT want a digital display like a JS> 7-segment or LCD though. JS> I want to be able to utilize these outputs to control others parts of JS> my circuitry (perhaps like voltage calibration).
JS> Example: JS> LED 1 (green) = -10-20 degrees, JS> LED 2 (yellow) = 20-30 degrees, JS> LED 3 (red) = 40+ degrees,
JS> I am open to all suggestions. JS> Thanks in advance.
J,
You might try crossposting to sci.electronics.design.
Your circuit needs a voltage reference and a window comparator. The voltage reference is used with a temperature probe and the window comparator will divide your output into 3 ranges. With some cmos gating you can readily light 3 separate leds.
A*s*i*m*o*v
... I worked hard to attach the electrodes to it.