|
Tractor Talk Discussion Board |
Re: Re: Re: Positive ground..?!
[ View Follow Ups ] [ Post Followup ] [ Return to Forum ]
Posted by uh . . . Dell (WA) on January 29, 2002 at 08:17:27 from (198.81.17.53):
In Reply to: Re: Re: Positive ground..?! posted by MarkB on January 28, 2002 at 16:55:45:
Mark........."12 volt alternators are designed to work with negative ground, not the other way around. You could make a positive ground alternator (just reverse the diodes), but negative ground was standardized by the time alternators were in common use"......NO, NO, NO, you just can't simply reverse the diodes. What ultimately caused 12 volt negative ground to become the standard electrical configuration was the switch to transistorized radios in 1956. Everyone just had to have the latest in radio technology. (Does that sound familiar?) The germanium audio Power Transistor Amplifier needed a heatsink to keep from melting its lil' ol'semi-conductor heart. Cheapest and eaziest heatsink was the metal radio chassis itself. Leave alone the problem of insulating the radio from the dash (which it is not insulated). The germanium power transistor is NPN, which means the collector must have negative potential. The collector is also the physically internally connected to the large metal transistor case for heatsinking. The collector is also the part that gets HOT. Vola...the reason for negative ground. The same line of reasoning for the semi-conductor diode trio in the alternator. HEATSINK! Use the alternators metal case as a heatsink. Manufacture the diode so the diode's metal case is physically internally the cathode for heatsinking purposses. Then the anode supplies positive electricity to the diode pigtail. I assume you realize innna 'lectricity, ya gotts ta hava goes innta annna cums outta. Semi-conductor power diodes use their metalic case for bi-directional duties, heatsink and electrical conductor. And so thats the reason for todays automotive electrical systems being "negative ground", POWER DIODES and POWER TRANSISTORS need HEATSINKS and your semi-conductor factorys manufacture them that way..........respectfully, Dell (WA)
Follow Ups:
Home
| Forums
Today's Featured Article -
Earthmaster Project Progress Just a little update on my Earthmaster......it's back from the dead! I pulled the head, and soaked the stuck valves with mystery oil overnight, re-installed the head, and bingo, the compression returned. But alas, my carb foiled me again, it would fire a second then flood out. After numerous dead ends for a replacement carb, I went to work fixing mine.I soldered new floats on the float arm, they came from an old motorcycle carb, replaced the packing on the throttle shaft with o-rings, cut new ga
... [Read Article]
Latest Ad:
1964 I-H 140 tractor with cultivators and sidedresser. Starts and runs good. Asking 2650. CALL RON AT 502-319-1952
[More Ads]
Copyright © 1997-2025 Yesterday's Tractor Co.
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V. Yesterday's Tractors - Antique Tractor HeadquartersWebsite Accessibility Policy |
|
