Can I put in a higher quality sensor in my DSLR?

I have a Nikon D40 and I'm at the point where a higher quality camera would benefit greatly. However, I can't really afford a new camera. Would it be possible to put in another sensor like one in a higher quality Nikon and would it be economical?

No. This isn't like changing out a video card or RAM. DSLR's are not designed & built like PC's.

Your D40 will take excellent images for a long time yet. Unless you are doing poster sized prints or high ISO shots, you don't need to change it.

No, sorry, and even the D40 body is really it's weakest point, basic AF and feature set.

Apart from the cost of replacing the CCD component and the processer, the labour cost would mean it was far from economically viable.

Some medium format cameras like the hassleblad / phase one / leafs had interchangable backs, but these are at stratospheric costs to begin with.

I have a colleague who still uses a D40 because it can sync with flash at high shutter speeds, something CMOS sensored cameras can't do. He uses it to shoot at the X-Games and NBA basketball games to supplement his full frame dSLR's

There's a lot of life left in your fine D40

IF you could replace the CCD with a new CMOS sensor (all the new dSLR's use them now) and the supporting electronics, would cost more than just simply buying say a new $700 D3100.

For now continue to use it to expand your vision of your world and learning how to push the envelop of the features your camera has always had. And while doing that, start saving your pennies for your next camera

In what way do you notice your pics from the D40 as being poor? My friend's D40 gives her excellent pics. Maybe you need some lessons in photography, maybe you should check the resolution and quality settings in the menu. If you get a downloaded file size lower than approx 2MB then your settings are wrong.

Please don't take this wrongly--D40 is a fine camera and will give the user beautiful photos - that is if he knows how to use it. If you're not happy with the way photos come out with that camera, upgrading it to another won't help.

Take a photography course. It's really worth the time and money.