The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: Fred Bloggs
User-Agent: Mozilla/5.0 (Windows; U; Win 9x 4.90; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0
X-Accept-Language: en-us, en
Subject: Re: zero-power toggle circuit; was, how to master electronics
References: <3DC517EB.firstname.lastname@example.org> <3DC57B4E.email@example.com> <firstname.lastname@example.org> <email@example.com> <3DD39D90.firstname.lastname@example.org>
Date: Fri, 15 Nov 2002 03:20:13 GMT
NNTP-Posting-Date: Thu, 14 Nov 2002 19:20:13 PST
Organization: EarthLink Inc. -- http://www.EarthLink.net
> Winfield Hill wrote:
>>High-side switching is dangerous, unless an effective form of
>>short-circuit protection is provided, e.g. shutoff, foldback
>>current limit, a quick fuse, etc. Low-side switching is used
>>in cars, etc., because it has the nice property that a wiring
>>short simply turns on the switched device. Recommended.
> I would have thought in wiring terms cars are mostly high side switching.
> With a -ve earth chassis used for a return most wires between switches and
> loads are +ve.
> Low side switching is frowned on in industrial controls systems because of
> that property. It is no doubt made illegal by some bloody european safety
> regulation or the other. Having things turn on due to the most common type
> of wiring short is generally more dangerous than having them turn off
> although personally I don't think it is anything to get that worked up
Right- I am not sure about the low side switching, seems to be an awful
lot of automotive high-side switching being done. And every single one
of these circuits is a straightforward implementation of the simple two
inverter latch- Win just likes to make things look much more involved
than they actually are. The drawback on all these circuits is that the
momentary switch does not have a terminal fixed to one of the rails.
View in a fixed-width font such as
| | / | | /
| | / / | /
| | / \ Rs | / <---PWR
| / MOSFET
| \ / \
| --- |
+--------o o-----+ SIMPLE INVERTER TOGGLE
--- SW NOT GND'D
| RsC>> SW BOUNCE
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup