Today's Message Index:
----------------------
1. 05:32 AM - Re: Re: OV protection circuit design (Robert L. Nuckolls, III)
2. 06:10 AM - HEADSET POWER SUPPLY (user9253)
3. 08:44 AM - Re: HEADSET POWER SUPPLY (Robert L. Nuckolls, III)
4. 09:12 AM - Re: Re: OV protection circuit design (Jeff Luckey)
5. 09:37 AM - Re: HEADSET POWER SUPPLY (user9253)
6. 10:31 AM - Re: Re: OV protection circuit design (Art Zemon)
7. 10:41 AM - Re: HEADSET POWER SUPPLY (Charlie England)
8. 12:42 PM - Re: Re: OV protection circuit design (Robert L. Nuckolls, III)
9. 01:19 PM - Re: Re: OV protection circuit design (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: OV protection circuit design |
At 08:55 PM 3/8/2020, you wrote:
>Bob,
>
>Those are very instructive videos. Thank you for sharing them. I
>will be passing them on to some friends.
Very good sir. That was a sad case to work.
A very nice LA-IVP went down and people got
hurt . . . some for life. It's a modern
allegory to the "for want of a nail" proverb.
But if there is potential for a valuable lesson
learned, this is one of them.
Bob . . .
Message 2
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| Subject: | HEADSET POWER SUPPLY |
A friend of mine wants to power his David Clark headsets from 14 VDC
aircraft power instead of using the 9 volt battery box that came with the
headset. He said that the electronics inside of the headset have been
replaced, so the model number of the headset is irrelevant.
My question is, can the headsets be powered directly by 14 VDC aircraft
power, or should the voltage be dropped to 9 VDC and some filter capacitors added?
Thanks, Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=495209#495209
Message 3
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| Subject: | Re: HEADSET POWER SUPPLY |
At 08:08 AM 3/9/2020, you wrote:
>
>A friend of mine wants to power his David Clark headsets from 14 VDC
>aircraft power instead of using the 9 volt battery box that came with the
>headset. He said that the electronics inside of the headset have been
>replaced, so the model number of the headset is irrelevant.
> My question is, can the headsets be powered directly by 14 VDC aircraft
>power, or should the voltage be dropped to 9 VDC and some filter
>capacitors added?
>Thanks, Joe
We cannot know if the device would run reliably
on 14v. The safe thing to do is duplicate the
obvious and provide a quiet 9v source. It's
a low-risk experiment . . . it will either
be quiet enough . . . or not. Start here:
Emacs!
The 3-terminal regulators are powerful noise
filters in themselves. Likelihood of success
is high.
Make sure there is a common ground between
head-set plug shells and the (-) lead to
the 9v battery. There is a remote chance
that the audio amplifier does not share
common ground with the ship's audio grounds.
Bob . . .
Message 4
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| Subject: | Re: OV protection circuit design |
Bob,
At what fuse rating does the breaker pop before the fuse?=C2- 30A, 40A, 5
0A... ???
Just curious...
-Jeff
On Monday, March 9, 2020, 05:40:25 AM PDT, Robert L. Nuckolls, III <nuc
kolls.bob@aeroelectric.com> wrote:
At 08:55 PM 3/8/2020, you wrote:
Bob,
Those are very instructive videos. Thank you for sharing them. I will bepas
sing them on to some friends.
=C2- Very good sir. That was a sad case to work.
=C2- A very nice LA-IVP went down and people got
=C2- hurt . . . some for life. It's a modern
=C2- allegory to the "for want of a nail" proverb.
=C2- But if there is potential for a valuable lesson
=C2- learned, this is one of them.
=C2- Bob . . .
Message 5
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| Subject: | Re: HEADSET POWER SUPPLY |
Bob, thanks for the great advice and schematic. Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=495212#495212
Message 6
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| Subject: | Re: OV protection circuit design |
Jeff,
Watch the two videos and you will understand that there is no answer to
your question.
-- Art Z.
On Mon, Mar 9, 2020 at 11:27 AM Jeff Luckey <jluckey@pacbell.net> wrote:
> Bob,
>
> At what fuse rating does the breaker pop before the fuse? 30A, 40A,
> 50A... ???
>
> Just curious...
>
> -Jeff
>
> On Monday, March 9, 2020, 05:40:25 AM PDT, Robert L. Nuckolls, III <
> nuckolls.bob@aeroelectric.com> wrote:
>
>
> At 08:55 PM 3/8/2020, you wrote:
>
> Bob,
>
> Those are very instructive videos. Thank you for sharing them. I will be
> passing them on to some friends.
>
>
> Very good sir. That was a sad case to work.
> A very nice LA-IVP went down and people got
> hurt . . . some for life. It's a modern
> allegory to the "for want of a nail" proverb.
>
> But if there is potential for a valuable lesson
> learned, this is one of them.
>
> Bob . . .
>
--
https://CheerfulCurmudgeon.com/
*Sooner meet a bereaved she-bear than a fool with his nonsense. *Proverbs
17:12
Message 7
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| Subject: | Re: HEADSET POWER SUPPLY |
On 3/9/2020 10:40 AM, Robert L. Nuckolls, III wrote:
> At 08:08 AM 3/9/2020, you wrote:
>>
>> A friend of mine wants to power his David Clark headsets from 14 VDC
>> aircraft power instead of using the 9 volt battery box that came with
>> the
>> headset. He said that the electronics inside of the headset have been
>> replaced, so the model number of the headset is irrelevant.
>> My question is, can the headsets be powered directly by 14 VDC aircraft
>> power, or should the voltage be dropped to 9 VDC and some filter
>> capacitors added?
>> Thanks, Joe
>
> We cannot know if the device would run reliably
> on 14v. The safe thing to do is duplicate the
> obvious and provide a quiet 9v source. It's
> a low-risk experiment . . . it will either
> be quiet enough . . . or not. Start here:
>
> Emacs!
>
> The 3-terminal regulators are powerful noise
> filters in themselves. Likelihood of success
> is high.
>
> Make sure there is a common ground between
> head-set plug shells and the (-) lead to
> the 9v battery. There is a remote chance
> that the audio amplifier does not share
> common ground with the ship's audio grounds.
>
>
> Bob . . .
>
FWIW, I've had excellent luck using LM78xx fixed voltage regulators with
no external components, as voltage dropping regulators in both cars and
airplanes. LM7809 would give 9V output. Wired similar to the 317, with
in/GND/out. I just used an LM7805 to power a serial output GPS puck (5V
power supply required), used as position source for a GRT HX EFIS.
No external components, no risk of drift, etc. In extremely low current
applications like mine, I could get away with no heat sink. Might be
different with the Bose; I have no idea on its power consumption.
Charlie
--
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Message 8
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| Subject: | Re: OV protection circuit design |
At 11:10 AM 3/9/2020, you wrote:
>Bob,
>
>At what fuse rating does the breaker pop before the fuse? 30A, 40A,
>50A... ???
>
>Just curious...
No hard and fast rule . . . both breakers and
fuses can be had in a range of trip profiles.
I've tested the ATO/ATC30 plastic fuses
against the miniature breakers popular in
aircraft with a goal of at least 3x head-room
with a 100A crowbar event.
I couldn't find my favorite 300A HE sensor
but did find a 400A that will let me repeat
the bench tests but I'll take a look at the
ATO40 fuse also.
Bob . . .
Message 9
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| Subject: | Re: OV protection circuit design |
At 11:10 AM 3/9/2020, you wrote:
>Bob,
>
>At what fuse rating does the breaker pop before the fuse? 30A, 40A,
>50A... ???
>
>Just curious...
No hard and fast rule . . . both breakers and
fuses can be had in a range of trip profiles.
I've tested the ATO/ATC30 plastic fuses
against the miniature breakers popular in
aircraft with a goal of at least 3x head-room
with a 100A crowbar event.
I couldn't find my favorite 300A HE sensor
but did find a 400A that will let me repeat
the bench tests but I'll take a look at the
ATO40 fuse also.
Bob . . .
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