Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site umd5.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!zehntel!hplabs!hao!seismo!umcp-cs!cvl!umd5!zben From: zben@umd5.UUCP Newsgroups: net.analog Subject: Re: Big Capacitors Message-ID: <259@umd5.UUCP> Date: Tue, 4-Dec-84 15:43:29 EST Article-I.D.: umd5.259 Posted: Tue Dec 4 15:43:29 1984 Date-Received: Thu, 6-Dec-84 06:31:30 EST References: <1812@sun.uucp> <1215@hou4b.UUCP> <6171@brl-tgr.ARPA> <10102@watmath.UUCP> Reply-To: zben@umd5Cranston.UUCP (Ben Cranston) Organization: U of Md, CSC, College Park, Md Lines: 31 Sorry, but I have seen about enough pseudo-scientific garbage on this subject to breakover and add my own two cents worth of pseudo-scientific garbage: > Try a battery! Your car probably has an electrolytic capacitor > consisting of a liquid electrolyte and lead plates...many Farads, I > think. > Seeing as the vague definition of a capacitor is "something which can > store an electric charge", a rechargeable battery seems like a wonderful > huge capacitor. Begin flame: Yes, thats just about vague enough to be meaningless. A more precise definition of a capacitor is that it stores energy IN THE ELECTRIC FIELD BETWEEN THE PLATES, just as an inductor stores energy in the magnetic field that cuts the windings. Now, a battery stores the energy chemically, not as an electric field, so a battery, strictly speaking, is not the same animal as a capacitor at all. You cannot make a resonant circuit with a battery (I don't think). The discharge rate is limited by the chemical reaction rate. Thats one huge differance between a capacitor and a battery. By the way, my homebrew machine (TI9900) was made from a Technico Super Starter kit, but I designed and built the power supply. I have 1/6 of a farad on the +5 supply! (Yes, the lights dim and it goes "buzz" for a few seconds when I turn it on. But +5 is clean!). The can is 160,000 mikes at 10 volts and cost about $4.00 at the local surplus store. Buy yourself 6 or 7 and you too can have a one farad capacitor! Bailed out of EE for CS, but I can still design power supplies... Ben Cranston