# Role of Resistance in Infrared Detectors

1. Jul 9, 2012

### nichthefish

Hi, I constructed a device that consists of two metal pads atop a semiconductor material. I'm still confused on the whole Ohms law thing. Infrared radiation strikes the metal, and we're testing it at different temperatures, but I don't know what happens from there. My questions are:

1. Is the voltage applied to one metal pad or both (to generate current?)
2. What is the role of resistance?
3. Not sure if this is too specific, but why is a wider range of resistance good?

I'm not sure if I made any sense, but I would appreciate any kind of help. Thanks!

2. Jul 9, 2012

### Drakkith

Staff Emeritus
Ohms law states the relationship between Current, Voltage, and Resistance in an electronic circuit. Specifically I=V/R, which means that the current is equal to the voltage divided by the resistance.

Most of what you are asking is covered in any basic electronics book. I suggest picking one up at any bookstore or from online.

3. Jul 9, 2012

### nichthefish

Thanks, I understand the actual law, I just don't know its importance in infrared detectors. That's my main question, sorry if I wasn't clear.

4. Jul 9, 2012

### CWatters

I'm not familiar with the design you are talking about but my thinking would be..

1) You apply a voltage between the pads and measure the current flowing. From that you calculate the resistance?
2) The resistance depends on the IR radaition?
3) If the amount the resistance varies is large the detector is more sensitive? eg smaller temperature changes can be detected?

5. Jul 9, 2012

### CWatters

Here you go...
http://en.wikipedia.org/wiki/Infrared_detector

So I suspect my earlier reply is along the right lines.