Groups > sci.electronics.design > #447344

Re: PNP for soft switch and reverse battery protection

From	rickman <gnuarm@gmail.com>
Newsgroups	sci.electronics.design
Subject	Re: PNP for soft switch and reverse battery protection
Date	2017-02-11 19:50 -0500
Organization	A noiseless patient Spider
Message-ID	<o7obck$tvq$2@dont-email.me> (permalink)
References	(6 earlier) <20170211-024908.341.0@Peabody.ssl.astraweb.com> <j30t9ctnntiflbibtauoutin79oubm77ie@4ax.com> <20170211-173832.807.0@Peabody.ssl.astraweb.com> <i2lu9c5sk10k9kiegets5pkiund5bod39d@4ax.com> <20170212-003118.759.0@Peabody.ssl.astraweb.com>

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On 2/11/2017 7:31 PM, Peabody wrote:
> Jim Thompson says...
>
>  > Oooops!  I misunderstood your original post.  I only
>  > tried reverse voltage protection, not turn-off via the
>  > transistor.
>
>  > Do you really need to turn off via the transistor rather
>  > than just a switch at the battery?
>
> Yes.  The whole point is not having to use a manual switch.
>
> Besides, it appears reverse polarity protection doesn't work
> if the power supply is more than 8V, which would include a
> 9V battery.
>
> Well, I'll keep working on this, but for now it looks like
> two P-channel mosfets will be needed, as others have
> suggested.

It's a long thread, maybe this was stated.  Is there a reason why a 
Schottky diode can't be used for reverse polarity protection?  That 
seems simpler than adding two transistors.  Maybe not.  Two of the same 
line item can be easier in fabrication than two line items.

-- 

Rick C

Thread

PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-09 13:16 -0600
  Re: PNP for soft switch and reverse battery protection John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-09 11:34 -0800
    Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-09 16:47 -0600
      Re: PNP for soft switch and reverse battery protection John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-09 15:40 -0800
        Re: PNP for soft switch and reverse battery protection bitrex <bitrex@de.lete.earthlink.net> - 2017-02-10 10:47 -0500
          Re: PNP for soft switch and reverse battery protection John Larkin <jjlarkin@highlandtechnology.com> - 2017-02-10 08:30 -0800
      Re: PNP for soft switch and reverse battery protection George Herold <gherold@teachspin.com> - 2017-02-10 07:25 -0800
        Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-10 11:37 -0600
          Re: PNP for soft switch and reverse battery protection Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-10 11:19 -0800
            Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 12:48 -0700
            Re: PNP for soft switch and reverse battery protection George Herold <gherold@teachspin.com> - 2017-02-10 12:24 -0800
          Re: PNP for soft switch and reverse battery protection George Herold <gherold@teachspin.com> - 2017-02-10 12:22 -0800
  Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-09 13:21 -0700
    Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-09 16:46 -0600
      Re: PNP for soft switch and reverse battery protection "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-09 17:01 -0600
        Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-09 18:59 -0700
          Re: PNP for soft switch and reverse battery protection "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-10 13:17 -0600
      Re: PNP for soft switch and reverse battery protection Winfield Hill <hill@rowland.harvard.edu> - 2017-02-10 14:29 -0800
        Re: PNP for soft switch and reverse battery protection Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-10 17:58 -0500
          Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 16:40 -0700
      Re: PNP for soft switch and reverse battery protection M Philbrook <jamie_ka1lpa@charter.net> - 2017-02-10 18:23 -0500
  Re: PNP for soft switch and reverse battery protection Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-09 14:55 -0800
  Re: PNP for soft switch and reverse battery protection bill.sloman@ieee.org - 2017-02-09 17:31 -0800
  Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 08:50 -0700
    Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-10 11:18 -0600
      Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 12:41 -0700
        Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-10 16:28 -0600
          Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 16:44 -0700
            Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-10 20:49 -0600
              Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 20:10 -0700
                Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-11 11:38 -0600
                Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-11 11:07 -0700
                Re: PNP for soft switch and reverse battery protection rickman <gnuarm@gmail.com> - 2017-02-11 18:46 -0500
                Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-11 11:15 -0700
                Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-11 18:31 -0600
                Re: PNP for soft switch and reverse battery protection rickman <gnuarm@gmail.com> - 2017-02-11 19:50 -0500
                Re: PNP for soft switch and reverse battery protection Clifford Heath <no.spam@please.net> - 2017-02-12 12:44 +1100
                Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-11 23:26 -0600
                Re: PNP for soft switch and reverse battery protection Clifford Heath <no.spam@please.net> - 2017-02-12 18:19 +1100
                Re: PNP for soft switch and reverse battery protection Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-12 08:18 -0800
                Re: PNP for soft switch and reverse battery protection rickman <gnuarm@gmail.com> - 2017-02-14 01:52 -0500
                Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-11 18:04 -0700
                Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-11 23:14 -0600
                Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-12 08:18 -0700
                Re: PNP for soft switch and reverse battery protection John Larkin <jjlarkin@highlandtechnology.com> - 2017-02-12 08:29 -0800
    Re: PNP for soft switch and reverse battery protection whit3rd <whit3rd@gmail.com> - 2017-02-10 13:54 -0800
  Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 08:53 -0700
  Re: PNP for soft switch and reverse battery protection M Philbrook <jamie_ka1lpa@charter.net> - 2017-02-10 18:08 -0500
    Re: PNP for soft switch and reverse battery protection Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-10 15:15 -0800
      Re: PNP for soft switch and reverse battery protection M Philbrook <jamie_ka1lpa@charter.net> - 2017-02-10 18:34 -0500
  Re: PNP for soft switch and reverse battery protection Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-11 12:47 -0700
  Re: PNP for soft switch and reverse battery protection Jasen Betts <jasen@xnet.co.nz> - 2017-02-14 06:13 +0000
    Re: PNP for soft switch and reverse battery protection whit3rd <whit3rd@gmail.com> - 2017-02-14 00:52 -0800
      Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-14 22:26 -0600
    Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-14 22:16 -0600
      Re: PNP for soft switch and reverse battery protection John Larkin <jjlarkin@highlandtechnology.com> - 2017-02-14 21:42 -0800
        Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-15 00:21 -0600
          Re: PNP for soft switch and reverse battery protection Jasen Betts <jasen@xnet.co.nz> - 2017-02-15 11:44 +0000
            Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-15 08:15 -0600
              Re: PNP for soft switch and reverse battery protection makolber@yahoo.com - 2017-02-15 09:30 -0800
                Re: PNP for soft switch and reverse battery protection Peabody <waybackNO584SPAM44@yahoo.com> - 2017-02-15 11:50 -0600
                Re: PNP for soft switch and reverse battery protection makolber@yahoo.com - 2017-02-15 10:07 -0800
                Re: PNP for soft switch and reverse battery protection "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-15 21:19 -0600
                Re: PNP for soft switch and reverse battery protection George Herold <gherold@teachspin.com> - 2017-02-15 11:30 -0800
                Re: PNP for soft switch and reverse battery protection makolber@yahoo.com - 2017-02-15 11:52 -0800
                Re: PNP for soft switch and reverse battery protection George Herold <gherold@teachspin.com> - 2017-02-15 12:00 -0800
          Re: PNP for soft switch and reverse battery protection John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-15 10:41 -0800

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