Make a Simplest Temperature Indicator Circuit

Posted on Feb 6, 2014

As we know that all semiconductors have this bad habit of changing its basic characteristics in response to ambient temperature changes. Especially basic electronic components like transistors and diodes are very much prone to their case temperature variations. The change with their characteristics with these devices is typically in terms of th

Make a Simplest Temperature Indicator Circuit
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e passage of voltage through them, which is directly proportional with the magnitude of the temperature difference surrounding them. Obviously since the diode is placed as the reference, it has to be placed in an environment with relatively consistent temperature conditions, otherwise the diode will also start changing its reference level causing error in the indication process. A LED is used here at the collector of the transistor, which directly interprets the transistor conditions and therefore helps to show how much temperature difference is taking place around the transistor. In this design the diode is placed at the ambient temperature or at the room temperature which the transistor is placed or attached to the heat source which needs to be measured. Caution must be maintained, not to exceed the temperature over the transistor above 120 degree Celsius, other wise the device may get burnt and damaged permanently.

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