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Groups > sci.electronics.design > #454514
| Subject | Re: Simple Low Voltage Shut Down |
|---|---|
| Newsgroups | sci.electronics.design |
| References | <Nl2DA.428151$fZ.218528@fx41.am4> <obisol016pi@drn.newsguy.com> <dbzDA.285202$2K7.267822@fx18.am4> <obmjib$f0c$3@dont-email.me> |
| From | Robert Miller <robert.miller@teledyne.com> |
| Message-ID | <jJBDA.324228$dI6.322446@fx31.am4> (permalink) |
| Organization | free.xsusenet.com |
| Date | 2017-04-01 10:35 +1100 |
On 01/04/17 09:03, rickman wrote: > On 3/31/2017 4:42 PM, 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. >> >> Maybe a dumb question, but, given the low current, would it be possible >> to power the amp through a zener diode? > > What would that accomplish other than losing a lot of power and voltage > to the amp? > The amp would be powered through the zener until the supply voltage is too low to cause breakdown. Then the zener would stop conducting. The effect of dynamic resistance may need to be factored in. I am willing to accept the standard diode voltage drop. Robert Miller
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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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