If I do not fully understand a technique, they will hit me with more and more power
Are "they" other students in your class? And are they attempting to learn an offensive technique compared to your defensive one?
I ask because they may be more focused on their own training than on yours if that is the case, and increase their power as they get more comfortable with their own technique or after getting warmed up. Only by speaking up will they notice that you might be uncomfortable with your own technique or with the power they are using. Even then, some people won't want to take it easy, what it really comes down to for those people is that they either really enjoy hitting things hard, or they just care a lot more about their own gain from this training than what they care about what you gain from it. (It seems commonly believed that going all-out means you get more out of the training, a debate I don't want to get into)
However, if it is an instructor, it could be that there is some communication gap. If you're naturally a tough person he might not realize just how fast/hard he is going if you're "toughing it out" and send no feedback. On the opposite end, if you wince at the lightest possible hit (This doesn't sound like the case but I figured I'd cover it) he may just gradually give up on going soft enough, he might not have the patience or control to train someone as softly as you'd like - which obviously could be a problem.
Note that he might think you are getting the technique right, and is slowly making it faster and faster (which also tends to mean harder and harder, though good control can overcome that) Again, you need to speak up for feedback on how your technique is, or ask him to continue at the previous pace where you are comfortable. Then, if nothing changes you know the issue isn't communication on your end and you'll have a better idea if you'd like to train somewhere else.
get mad when I beat them in sparring
Assuming you didn't ask them to take it easy, then win and trash-talk them, in which case just about anyone would be a little angry (and take it a bit more seriously next time), I would say that being angry for losing is understandable but unfortunate. It's too bad that their sportsmanship is poor, but there's not much you can do about that other than (bowing/shaking hands/showing respect) to each other.
he leg swept me by surprise... on the hard wood floor
The way you phrase it makes it seem like he did this in anger and frustration in an exercise that, while arguably you could have been prepared for a leg sweep, was not set up for that. Even if the rules of the exercise (if there were any) allowed leg sweeps, he shouldn't be striking out in anger with the true intention of hurting you. This is a major flag that I would take seriously.
A lot of times in my classes, if I do any technique wrong, I pay the price of becoming an example of what not to do before they do a really hard joint lock or smack and or grab my hands and arms really hard to the point I can actually feel my eyes tear up
The circumstances around how you and the instructor practice in this case is kind of important to how to take this. If you are volunteering to demonstrate a technique in front of everyone, it might be that the instructor would do this to anyone who made the mistake. In fact, if it were a more experienced person, he may ask that person to make a mistake on purpose.
This doesn't mean he should be rough in his demonstration.
If he is calling you up, I would assume he thinks you are now "the safe bet" as a sparring dummy, he knows you're new enough to make mistakes and can demonstrate his point without you complaining. The considerable size difference, if there is one, could also be a major factor. He might be able to show off fancy moves on a lighter opponent, or the technique might be better demonstrated by a lighter person against him.
If this is a partner exercise, whoever gets stuck with the instructor is likely going to be the person who is demonstrated on.
In every case, I would ask him 1 on 1 either not to demonstrate on me, or to take it easy when demonstrating on me, though on the partner case you may have to deal with having someone else as a partner then. You are not there to get beat up. If it still continues, he may have character flaws that require you to find a new instructor.
Ultimately, my answer tries to explore unintentional possibilities. It still very could be some form of feeling good about themselves for "beating" or "man-handling" a woman. If you don't think anything I've said is a possibility and think these happenings are in any way intentional, I would try to find a different place to train. Let them beat each other up, and find a more respectful place to train.