To 50,
A few things to point out----------
1. Electronic components, because they don't move around, are ideal macro subjects.
2. As Maximus pointed out, the only real way, is to have light, more light, and more light, so you can use F22 or an even a slower F stop. A light box may be ideal for evenly distributed light, but very slow shutter speeds are easily permitted as long as nothing moves and your tripod is sturdy.
3. An autofocus lens in your macro case is worthless, simply because you don't focus with the lens, its best to move the Camera closer or further to the object to achieve sharp focus, ideally with some rack and pinion mechanism mounted on your tripod.
4. Then this forum has ignored the the real question, in what formatting how are the resultant photo's going to be viewed by the end user? If they will be published in some catalog in say 3"x5" format or smaller, a super high megapixel count will not be needed, because no one will see the difference. But if they are going to be viewed blown up to 11"x14" size or larger, sharp detail then becomes critical and you better make sure, the result image covers every square millimeter of the camera sensor because cropping will then become human eye visible.
5. Then we somewhat ignore the human factor, you are probably going to be adjusting your focus with your own eye looking through the Camera view finder. If your own human body can comfortable look through the viewfinder you can take many photos of various components in almost an assembly line method, but if you have contort your body in a twisted uncomfortable fashion, it not only going to really slow you down, after some period of time your whole body will hurt. In my case the only way I get my el cheapo tripod to have rack and pion focus is to view straight up and down. But its probably better for human comfort to have about a 45 degree down angle while sitting in a chair.