Everything posted by cjk2
cjk2 replied to a topic in Theory articlesThe title of the book is "Getting Started in Electronics" by Forrest M. Mims. I own the book and I think it is probably what got me started in electronics. I would be glad to host it so everyone can get a copy of it, but I am slightly worried about copyright law. Perhaps if I put it in a zip file with a password on it? Then I'll post the password here so only people here can get it, and I won't get sued. Does everyone here either have Winzip, or windows XP to open it?
High Voltage Cap charger
cjk2 replied to f4cepl4nt's topic in High Voltage StuffYou may want to look into using a "boost converter". That way you only need an inductor and dont have to make a 900v transformer.
cjk2 replied to f4cepl4nt's topic in High Voltage StuffWell, I can see your reasoning, but it is very hard to actually make this work. The problem you run into is that the second transfromers sees many more volts per turn than it was desiged for. This causes two problems: overheating in the windings due to overcurrent, and the biggest problem, core stauration. If you saturate the core(by appily too much voltage to a winding of too few turns) the transformer will overheat and will not output anything useful. There are two ways around these problems: 1. use larger cores, or 2. use a higher frequency to drive the transformers(the transformers must now be made of a good quality material. Iron will not work past a few hundred Hz's due to eddy currents, so ferite is the best choice.) Although your idea would be a good one, due to the above reasons, it will almost always be a better idea to simply increase the ratio of one transformer to get the voltage you want, and not worry about using two. I hope that cleared things up... Let me know if you need any more help. Chris
cjk2 replied to trpulot's topic in Theory articlesThe caps around the regulator are just to help filter out noise and are really not needed at all. If you still feel a need to put then in, basicaly any small caps will do. The section you are talking about uses a 7805 voltage regulator to create a constant current source, so the current should be the same no matter what the voltage is in the batteries. even if the batteries are replaced with a short circuit, the current should always be the same. To measure current into the batteries/short where batteries would be, just use the 10 ohm resistor as a kind of "shunt". Just measure the voltage dropped across the resistor and move the decimal a few places to get current in miliamps. I forget which direction to move it but just try it and see. Somebody correct me if any of this advice is bad, but I think it all made sence.
cjk2 replied to a topic in High Voltage StuffThe output of a MOT is taken between the core and the only one connector on the secondary coil. There will also be a low voltage winding of a few turns of fairly big wire. This can be removed as it is likely useless. You will not be able to ge 4.2kv out of a single MOT. To do that you need a doubler which will give you around 4kvdc. Please use caution so you don't kill yourself. MOTs can be very dangerous. Also, balast it at around 1000w or you will blow a fuse.