Groups > sci.electronics.design > #454530

Re: Simple Low Voltage Shut Down

From	Winfield Hill <hill@rowland.harvard.edu>
Newsgroups	sci.electronics.design
Subject	Re: Simple Low Voltage Shut Down
Date	2017-03-31 17:56 -0700
Organization	Rowland Institute
Message-ID	<obmtr302o8c@drn.newsguy.com> (permalink)
References	<Nl2DA.428151$fZ.218528@fx41.am4> <obisol016pi@drn.newsguy.com> <dbzDA.285202$2K7.267822@fx18.am4>

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Robert Miller wrote...
>
>On 30/03/17 23:13, Winfield Hill wrote:
>> Robert Miller wrote...
>>>
>>> I have a little circuit consisting of an LM358 and
>>> BC547 emitter follower. It runs off 4 x AAA alkaline
>>> batteries and consumes about 50mA.
>>>
>>> What is the simplest way, without consuming additional
>>> power, of disabling the output from the LM358 when
>>> the battery voltage drops below around 4V?
>>
>> .
>> . --+-----E   C----
>> .   |       B
>> .  6.2k     |  ZTX718
>> .   |      470
>> .   |       |
>> .   |       K
>> .   +-----R    TL431
>> .   |       A  $0.40
>> .  10k      |
>> .   |       |
>> . --+-------+------
>>
>>
>
> That's a neat little circuit, but I was hoping for
> something passive.

 In engineering terms, passive means no transistors.
 Really?  How could that work?  My simple circuit is
 passive in the sense that no other power is required.
 But I do suggest the hysteresis version, with more
 hysteresis to force shutoff after the battery dies.


-- 
 Thanks,
    - Win

Thread

Simple Low Voltage Shut Down Robert Miller <robert.miller@teledyne.com> - 2017-03-30 18:21 +1100
  Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-30 05:13 -0700
    Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-30 10:20 -0700
      Re: Simple Low Voltage Shut Down Tim Wescott <seemywebsite@myfooter.really> - 2017-03-30 14:39 -0500
    Re: Simple Low Voltage Shut Down Robert Miller <robert.miller@teledyne.com> - 2017-04-01 07:42 +1100
      Re: Simple Low Voltage Shut Down rickman <gnuarm@gmail.com> - 2017-03-31 18:03 -0400
        Re: Simple Low Voltage Shut Down Robert Miller <robert.miller@teledyne.com> - 2017-04-01 10:35 +1100
          Re: Simple Low Voltage Shut Down rickman <gnuarm@gmail.com> - 2017-03-31 19:49 -0400
      Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-31 17:56 -0700
        Re: Simple Low Voltage Shut Down Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-04-01 11:17 -0400
  Re: Simple Low Voltage Shut Down John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-30 07:14 -0700
  Re: Simple Low Voltage Shut Down Tim Wescott <tim@seemywebsite.com> - 2017-03-30 12:19 -0500
    Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-30 13:18 -0700
      Re: Simple Low Voltage Shut Down Tim Wescott <seemywebsite@myfooter.really> - 2017-03-30 15:52 -0500
        Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-30 14:31 -0700
          Re: Simple Low Voltage Shut Down mike <ham789@netzero.net> - 2017-03-30 15:02 -0700

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