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Re: PNP for soft switch and reverse battery protection

Newsgroups	sci.electronics.design
Subject	Re: PNP for soft switch and reverse battery protection
From	Peabody <waybackNO584SPAM44@yahoo.com>
Date	2017-02-10 20:49 -0600
Message-ID	<20170211-024908.341.0@Peabody.ssl.astraweb.com> (permalink)
References	(1 earlier) <p4or9c5ok39q22hk1of4rb415h2ctuvnjn@4ax.com> <20170210-171843.415.0@Peabody.ssl.astraweb.com> <jp5s9chcjaikirci9ohmlcuvtth3vaus98@4ax.com> <20170210-222822.719.0@Peabody.ssl.astraweb.com> <9vjs9c9r5tpajteve6qgrqqu949ccls61r@4ax.com>
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Jim Thompson says...

 > You have R1 the wrong way around in the
 > emitter-toward-load mode.  And it should be about the
 > same value as the bias resistor.

 > And lose the diode.

With the transistor in the backwards orientation, and V+ at
12V:

I made all three resistors 47K, and removed the diode.

I still get C-E current with the base open.  If I move R1 to
the emitter side, it INCREASES the OFF current from 75 uA to
200 uA.  So that makes things worse.  

I tested three NPN transistors the same way - connecting C
or E to 12V through a 47K resistor with the other
connected to ground, but with the base open, and got similar
results.  If I connect C and E in normal polarity, no
current flows (because there is no base current), but when I
reverse the polarity of the C and E connections, I get
current - even though there is no base current.

So this effect appears to hold for all my bipolar
transistors so far.  What I don't know is whether the
voltage at which this current flow begins to happen is
related to any datasheet parameter.

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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