ron@brl-tgr.ARPA (Ron Natalie <ron>) (12/07/84)
OK, first I apologize for calling who ever it was an asshole for originally posting the battery is a capacitor line. It occurred when I was in a rotten mood and my urge to flame overrode my rule to be nice no matter how silly someone's submission is. > > Another way of looking at the battery vs capacitor controversy is the effect > that a battery can have as a ripple filter. If you put a battery (may not have > to be rechargeable) across a power supply, you'd tend to see very little AC in > the load. > Foo, this is also silly. I put 25 volt capacitor on a five volt supply, and the ripple dimishes. I put a five volt battery (If I can find one) on the line and when I exceed the current capacity of the battery the ripple returns. If I now switch the power supply to 7 volts the battery and/or the power supply blow up. The capacitor still works. Batteries also tend to lose any usefullness when the load increases. The battery here is playing voltage regulator not filter. Look at a cheap calculator cord sometime. The thin windings limit the current to the nicads, but the battery is providing the voltage regulation. That is why you are warned not to use the charger to power the calculator without the batteries in place. A battery is a resistor: Hey, I take a five volt supply with a constant current of 25 milliamp and put a D cell in series with it (backwards) and I get a 1.5 volt voltage drop, wow... E = IR 1.5 = .025R R = 1.5/.025 An effective 60 ohm resistor. Actually, I see resistors and batteries used interchangably to provide voltage bias more than I see Capacitors filtering AC ripple out of power supplies. -Ron
winkg@vice.UUCP (Wink Gross) (12/11/84)
You're losing ground fast (pun intended). Put two capacitors each charged to 1.5v in series and you will get 3v. What's the "something else" that you're expecting? Most of us can see that a battery is a highly non-linear capacitor, and, since they both store charge, it is unlikely that we're going to confuse a battery/capacitor with a resistor. wink gross tektronix, inc.