Msg: 522 *Conference*
09-19-91 22:50:43
From: TRACY ALLEN
To : RICHARD HANSON
Subj: REPLY TO MSG #482 (POWER PILLOW)
10 CLS:SOUND1000,10 20 PRINT"How come _I_ got stuck at Ft. Mamouth, NJ?" 30 INPUT"La Jolla!";STORY$ ------------------------------- The theory has to do with anything electronic where two gadgets share the same wiring. The problem comes when one gadget draws a heavy current while the other is sensitive to power supply voltage changes. a b c -------->--------------->-------- | | | + | | battery sensitive heavy - | | | | | -------<----------------<--------- f e d Heavy current flows from the battery around the loop abcdef. The wires ab and ef have electrical resistance. So (ohm's law!) the voltage at c is less than at b is less than at a. E.g. Think of how a light bulb in your house or car goes dim when heavy current is drawn by a washing machine or a starter motor on the same circuit. Don't put your brake lights on the same circuit as the headlights! The model 100 is very sensitive to sudden drops in its power supply voltage. Sudden drops can trigger the low-battery detection circuit. Thus when you hook up a disk drive to the same battery the computer might turn off. It is better to wire it as follows: a c -------->--------------->-------- ----------->------ b | | | | + | | battery sensitive heavy - | | | | | --------------<--- e | -------<----------------<--------- f d Each device has its own direct connection to the battery, so there is no voltage drop due to shared wiring. Still, the battery has to be a good one, so the battery voltage itself doesn't drop when the heavy load comes on. -- Tracy