Does this device exist?

I'm looking for some type of semiconductor device that has a very high
impedence gate that is OFF when high enough voltage is present. So a
capacitor could be charged, connected to the device, and because the
impedence is so high the capacitor is discharged very slowly. And
while connected and the voltage is high enough the device stays off.
When the voltage drops low enough the device turns on.
Thanks,
Eric

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[Maynard A. Philbrook Jr.]

In article <a0vph99dq1om6enq6k12q4c4lo09530884@4ax.com>,
etpm@whidbey.com says...

I'm looking for some type of semiconductor device that has a very high
impedence gate that is OFF when high enough voltage is present. So a
capacitor could be charged, connected to the device, and because the
impedence is so high the capacitor is discharged very slowly. And
while connected and the voltage is high enough the device stays off.
When the voltage drops low enough the device turns on.
Thanks,
Eric

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P channel Depletion mode MOSFET?

Jamie

 

[George Herold]

On Sunday, March 9, 2014 7:43:19 PM UTC-4, et...@whidbey.com wrote:

I'm looking for some type of semiconductor device that has a very high

impedence gate that is OFF when high enough voltage is present. So a
capacitor could be charged, connected to the device, and because the
impedence is so high the capacitor is discharged very slowly. And
while connected and the voltage is high enough the device stays off.
When the voltage drops low enough the device turns on.
Thanks,
Eric

A Jfet is on with zero (gate-source) voltage. You need a negative voltage to turn it off.
(Would that work? What are you trying to do?)

George H.

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[Glenn]

On 10/03/14 00.43, etpm@whidbey.com wrote:

I'm looking for some type of semiconductor device that has a very high
impedence gate that is OFF when high enough voltage is present. So a
capacitor could be charged, connected to the device, and because the
impedence is so high the capacitor is discharged very slowly. And
while connected and the voltage is high enough the device stays off.
When the voltage drops low enough the device turns on.
Thanks,
Eric

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A diode with a resistor?:

http://www.makeitsolar.com/images/schematic_solarbatterycharger004.jpg

-

Better charger:

Schematic of the Solar Charger Circuit:
http://www.electroschematics.com/4746/solar-charger-circuit/

-

Advanced:

DC to DC converter/smps? This can also be more efficient.

https://en.wikipedia.org/wiki/DC-to-DC_converter
https://en.wikipedia.org/wiki/Switched-mode_power_supply

https://en.wikipedia.org/wiki/Category:Electrical_power_conversion

e.g.

Needs AC:
https://en.wikipedia.org/wiki/Voltage_multiplier


Step by Step Hacking a Disposable Camera Flash Unit to Power a Geiger Tube:
http://madscientisthut.com/wordpress/daily-blog/hacking-a-disposable-camera-flash-unit-to-power-a-geiger-tube/

/Glenn

 

On Mon, 10 Mar 2014 12:05:59 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Sunday, March 9, 2014 7:43:19 PM UTC-4, et...@whidbey.com wrote:
I'm looking for some type of semiconductor device that has a very high

impedence gate that is OFF when high enough voltage is present. So a
capacitor could be charged, connected to the device, and because the
impedence is so high the capacitor is discharged very slowly. And
while connected and the voltage is high enough the device stays off.
When the voltage drops low enough the device turns on.
Thanks,
Eric

A Jfet is on with zero (gate-source) voltage. You need a negative voltage to turn it off.
(Would that work? What are you trying to do?)

George H.



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Greetings George,
Wall warts are always using power even when the device to be powered
is not connected. I know the amount of power used is small but I would
like to be able to avoid it. So I was wondering how I could disconnect
the wall wart from the mains whenever the powered device is turned
off. So when the load is removed from the wall wart it disconnects
from the mains and then reconnects automatically when a load is
connected. I was thinking that maybe a cap could be charged which
would keep the wall wart off. When the cap voltage drops too low the
wall wart would turn on again, the cap would charge, and then the wall
wart would again be disconnected from the mains. When a load was put
on the wall wart it would keep the cap discharged.
Eric

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[George Herold]

On Monday, March 10, 2014 3:50:10 PM UTC-4, et...@whidbey.com wrote:

On Mon, 10 Mar 2014 12:05:59 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:
snip question.

A Jfet is on with zero (gate-source) voltage. You need a negative voltage to turn it off.

(Would that work? What are you trying to do?)

http://www.avast.com

Greetings George,

Wall warts are always using power even when the device to be powered
is not connected. I know the amount of power used is small but I would
like to be able to avoid it. So I was wondering how I could disconnect
the wall wart from the mains whenever the powered device is turned
off. So when the load is removed from the wall wart it disconnects
from the mains and then reconnects automatically when a load is
connected. I was thinking that maybe a cap could be charged which
would keep the wall wart off. When the cap voltage drops too low the
wall wart would turn on again, the cap would charge, and then the wall
wart would again be disconnected from the mains. When a load was put
on the wall wart it would keep the cap discharged.

Eric

Hi Eric, I'm thinking a wall switch is going to be the cheapest/ easiest approach. People are always trying to save these little bits of power...
And the large bits are ignored. (Better windows and insulation, smaller cars... etc.)
I wonder if the energy you'd save over the life of the wall wart would be more than the energy to make the parts that go into the "energy saving" add-on?

George H.

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[George Herold]

On Tuesday, March 11, 2014 12:51:09 PM UTC-4, et...@whidbey.com wrote:

On Tue, 11 Mar 2014 06:47:14 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:



On Monday, March 10, 2014 3:50:10 PM UTC-4, et...@whidbey.com wrote:

On Mon, 10 Mar 2014 12:05:59 -0700 (PDT), George Herold



gherold@teachspin.com> wrote:

snip question.





A Jfet is on with zero (gate-source) voltage. You need a negative voltage to turn it off.



(Would that work? What are you trying to do?)



http://www.avast.com



Greetings George,



Wall warts are always using power even when the device to be powered

is not connected. I know the amount of power used is small but I would

like to be able to avoid it. So I was wondering how I could disconnect

the wall wart from the mains whenever the powered device is turned

off. So when the load is removed from the wall wart it disconnects

from the mains and then reconnects automatically when a load is

connected. I was thinking that maybe a cap could be charged which

would keep the wall wart off. When the cap voltage drops too low the

wall wart would turn on again, the cap would charge, and then the wall

wart would again be disconnected from the mains. When a load was put

on the wall wart it would keep the cap discharged.



Eric



Hi Eric, I'm thinking a wall switch is going to be the cheapest/ easiest approach. People are always trying to save these little bits of power...

And the large bits are ignored. (Better windows and insulation, smaller cars... etc.)

I wonder if the energy you'd save over the life of the wall wart would be more than the energy to make the parts that go into the "energy saving" add-on?



George H.





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I don't know if the energy saved would cover the cost of the extra
parts. I have done the major things to save energy. Even all the
interal walls are insulated so that rooms can be kept at a different
temps. Almost none of the receptacles are switched however. So the
wall warts need to be unplugged.

Eric

Hi Eric, I'm sorry I didn't mean to imply that you were wasteful.
(In fact it sounds like you are more dutiful than myself. We've got these big bay windows in the dining room, and I tell myslef each autumn, before the cold weather comes, that I should go and have some extra internal windows made for them. They are double pained but still on those cold winter nights... oh they do have some thick curtains.... but enough of that.)

So I've got a box with power connectors and a 1 ohm sereis resistor. (I use it to look at power draw from various instruments. I plugged in a Phihong 5V /1A wall wart. It drew about 9 mA with no load. So call it about 1 Watt of power. (OK for those experts I'm assuming I and V are in phase, but I have no proof of that.) Anyway if I left this on all year that's about 9k hours, so 9 kW-hours. It'd cost me a buck or so.
(Does it matter that all my electricity comes from the nearby windmills?)
For fun, a larger Astrodyne (~50W) brick on a rope draws about 40mA.

George H.

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[George Herold]

On Tuesday, March 11, 2014 3:12:31 PM UTC-4, George Herold wrote:
<snip>

Hi Eric, I'm sorry I didn't mean to imply that you were wasteful.

(In fact it sounds like you are more dutiful than myself. We've got these big bay windows in the dining room, and I tell myslef each autumn, before the cold weather comes, that I should go and have some extra internal windows made for them. They are double pained but still on those cold winter nights... oh
(Grumble double **paned**, excuse my spelling.... maybe they're double pained when you break one and have to replace it :^)

they do have some thick curtains.... but enough of that.)

So I've got a box with power connectors and a 1 ohm sereis resistor. (I use it to look at power draw from various instruments. I plugged in a Phihong 5V /1A wall wart. It drew about 9 mA with no load. So call it about 1 Watt of power. (OK for those experts I'm assuming I and V are in phase, but I have no proof of that.) Anyway if I left this on all year that's about 9k hours, so 9 kW-hours. It'd cost me a buck or so.

(Does it matter that all my electricity comes from the nearby windmills?)

For fun, a larger Astrodyne (~50W) brick on a rope draws about 40mA.



George H.







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On Tue, 11 Mar 2014 06:47:14 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Monday, March 10, 2014 3:50:10 PM UTC-4, et...@whidbey.com wrote:
On Mon, 10 Mar 2014 12:05:59 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:
snip question.


A Jfet is on with zero (gate-source) voltage. You need a negative voltage to turn it off.

(Would that work? What are you trying to do?)

http://www.avast.com

Greetings George,

Wall warts are always using power even when the device to be powered
is not connected. I know the amount of power used is small but I would
like to be able to avoid it. So I was wondering how I could disconnect
the wall wart from the mains whenever the powered device is turned
off. So when the load is removed from the wall wart it disconnects
from the mains and then reconnects automatically when a load is
connected. I was thinking that maybe a cap could be charged which
would keep the wall wart off. When the cap voltage drops too low the
wall wart would turn on again, the cap would charge, and then the wall
wart would again be disconnected from the mains. When a load was put
on the wall wart it would keep the cap discharged.

Eric

Hi Eric, I'm thinking a wall switch is going to be the cheapest/ easiest approach. People are always trying to save these little bits of power...
And the large bits are ignored. (Better windows and insulation, smaller cars... etc.)
I wonder if the energy you'd save over the life of the wall wart would be more than the energy to make the parts that go into the "energy saving" add-on?

George H.


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I don't know if the energy saved would cover the cost of the extra
parts. I have done the major things to save energy. Even all the
internal walls are insulated so that rooms can be kept at a different
temps. Almost none of the receptacles are switched however. So the
wall warts need to be unplugged.
Eric

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[Phil Hobbs]

On 03/11/2014 03:12 PM, George Herold wrote:

On Tuesday, March 11, 2014 12:51:09 PM UTC-4, et...@whidbey.com
wrote:
On Tue, 11 Mar 2014 06:47:14 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:



On Monday, March 10, 2014 3:50:10 PM UTC-4, et...@whidbey.com
wrote:

On Mon, 10 Mar 2014 12:05:59 -0700 (PDT), George Herold



gherold@teachspin.com> wrote:

snip question.





A Jfet is on with zero (gate-source) voltage. You need a
negative voltage to turn it off.



(Would that work? What are you trying to do?)



http://www.avast.com



Greetings George,



Wall warts are always using power even when the device to be
powered

is not connected. I know the amount of power used is small but
I would

like to be able to avoid it. So I was wondering how I could
disconnect

the wall wart from the mains whenever the powered device is
turned

off. So when the load is removed from the wall wart it
disconnects

from the mains and then reconnects automatically when a load
is

connected. I was thinking that maybe a cap could be charged
which

would keep the wall wart off. When the cap voltage drops too
low the

wall wart would turn on again, the cap would charge, and then
the wall

wart would again be disconnected from the mains. When a load
was put

on the wall wart it would keep the cap discharged.



Eric



Hi Eric, I'm thinking a wall switch is going to be the cheapest/
easiest approach. People are always trying to save these little
bits of power...

And the large bits are ignored. (Better windows and insulation,
smaller cars... etc.)

I wonder if the energy you'd save over the life of the wall wart
would be more than the energy to make the parts that go into the
"energy saving" add-on?



George H.





---



This email is free from viruses and malware because avast!
Antivirus protection is active.



http://www.avast.com

I don't know if the energy saved would cover the cost of the extra
parts. I have done the major things to save energy. Even all the
interal walls are insulated so that rooms can be kept at a
different temps. Almost none of the receptacles are switched
however. So the wall warts need to be unplugged.

Eric

Hi Eric, I'm sorry I didn't mean to imply that you were wasteful.
(In fact it sounds like you are more dutiful than myself. We've got
these big bay windows in the dining room, and I tell myslef each
autumn, before the cold weather comes, that I should go and have some
extra internal windows made for them. They are double pained but
still on those cold winter nights... oh they do have some thick
curtains.... but enough of that.)

Your first mistake was living in Buffalo.

Cheers

Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net