Hi, Im fairly new to magnetism and had a few questions regaring the construction of electromagnets. Im trying to build one for a simple application and was hoping for some advice. My application requires a small, preferably short, large-radius cylindrical electromagnet that will act as a permanent magnet when turned on. My questions are as follows: 1) What properties of an electromagnet effect its magnetic field strength? Does the size of the core matter? The length of the coil? The thickness of the coil? The gauge of wire used for the coil? The core, is iron way better than steel? The current? What is an easily accessable source of decent current for a strong magnetic field strength? The voltage? 2) How long does Hysteresis last? If the electromagnet is on, and then turned off will the magnetic field strength decrease significantly or does hysteresis keep the magnetic field just as strong initially? 3) Will an electromagnets north pole repel a permanent magnets north pole the same as two permanent magnets poles would? 4) Ive been doing research in magnetics and related topics for an internship of mine, and have been having trouble finding sources about magnetic analysis of a small metal structure. Does anyone know of a way I could get info about magnetic analysis of small nickle structures. The application requires magnetic fields to guide them through a fluid filled maze. Anyways, my job is to design and fabricate the structures, although when designing them I have to do magnetic analysis of the metal skeletons before fabricating them. I have never done this before and am looking for a source to help me learn. Thats pretty much it. I would greatly appreciate any feedback on any of the questions. Thank you so much for your time and help.