heating up a Resistor

Dorling

I need the javelin stamp to heat up a temperature sensor (LM35). I plan to do so by using a 100R 6W Resistor. If I connect 12v and GND to the resistor it does heat up. I need this to be done by the javelin stamp. So my program at control when it is on or off! This is going to be use in a temperature control system. There is a Fan to cool the sensor down this is done by a L293D.

I plan to use a transistor or a darlington transistor or maybe a relay would be best. If any one get out me out as I don't want to blow my javelin up!

Thanks

Jonathan

Post Edited (Dorling) : 6/5/2007 9:45:41 PM GMT

D Faust

You could use an optoisolator to turn this on and off and keep the crcuits separate.· I do not think that one of these requires a lot of amperage like relays, so you wouldn't have to use a transitor to control it.(not sure)· A transitor could probably do the job as well.

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D Faust

Dorling

so if I was to use a optoisolator as in this one http://www.maplin.co.uk/images/300/C0195.jpg which is part http://www.maplin.co.uk/Search.aspx?criteria=Opto-isolator&source=15&SD=Y

(javelin)CPU.pin0 ----> pin1 (Opto Transistor)
GND----pin 2 (Opto Transistor)
Vss(12v) ---- RESISTOR----pin 16 (Opto Transistor)
GND----pin 17 (Opto Transistor)

so when CPU.pin0 is high it is heating the RESISTOR up and when it is off it is NOT heating it up!

Jonathan