Forums

"reverse diode"

Started by jon....@gmail.com July 9, 2012
Is there a passive device similar to a diode that has low impedance at 0 fo=
rward voltage and high impedance at some larger voltage?

e.g., flip the diode curve horizontally then center the knee of the several=
 hundred mV above 0V.

One can emulate such a device a number of ways more or less but can one be =
made based on fundamental physical principles so that it behaves very simil=
ar to a "reverse diode"(by which I do not mean a reverse biased diode... so=
 please do not conflate the two).

Is there any simple reason why such a semiconductor based device can not ex=
ist? i.e., Is it possible to have a semiconductor device with an IV curve t=
hat **looks** like I(V) =3D 1/V or 1/V^2?


On Sun, 8 Jul 2012 22:11:05 -0700 (PDT), "jon.jukoba@gmail.com"
<jon.jukoba@gmail.com> wrote:

>e.g., flip the diode curve horizontally then center the >knee of the several hundred mV above 0V.
There will always be a junction potential to overcome.
On 2012-07-09, jon.jukoba@gmail.com <jon.jukoba@gmail.com> wrote:
> Is there a passive device similar to a diode that has low impedance > at 0 forward voltage and high impedance at some larger voltage?
1N5309
> e.g., flip the diode curve horizontally then center the knee of the several hundred mV above 0V.
could be tricky.
> > One can emulate such a device a number of ways more or less but can one be made based on fundamental physical principles so that it behaves very similar to a "reverse diode"(by which I do not mean a reverse biased diode... so please do not conflate the two). > > Is there any simple reason why such a semiconductor based device can not exist? i.e., Is it possible to have a semiconductor device with an IV curve that **looks** like I(V) = 1/V or 1/V^2? >
Ohm's law is your enemy. -- &#9858;&#9859; 100% natural --- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net ---
On 2012-07-09, Chieftain of the Carpet Crawlers <theslipperman@thebarattheendoftheuniverse.org> wrote:
> On Sun, 8 Jul 2012 22:11:05 -0700 (PDT), "jon.jukoba@gmail.com" ><jon.jukoba@gmail.com> wrote: > >>e.g., flip the diode curve horizontally then center the >>knee of the several hundred mV above 0V. > > There will always be a junction potential to overcome.
in a JFET? -- &#9858;&#9859; 100% natural --- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net ---
On 9 Jul 2012 08:53:12 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

>On 2012-07-09, Chieftain of the Carpet Crawlers <theslipperman@thebarattheendoftheuniverse.org> wrote: >> On Sun, 8 Jul 2012 22:11:05 -0700 (PDT), "jon.jukoba@gmail.com" >><jon.jukoba@gmail.com> wrote: >> >>>e.g., flip the diode curve horizontally then center the >>>knee of the several hundred mV above 0V. >> >> There will always be a junction potential to overcome. > >in a JFET?
In a DIODE junction. Learn to read.
On Monday, July 9, 2012 7:11:05 AM UTC+2, jon wrote:
> Is there a passive device similar to a diode that has low impedance at 0 =
forward voltage and high impedance at some larger voltage?
>=20 > e.g., flip the diode curve horizontally then center the knee of the sever=
al hundred mV above 0V.
>=20 > One can emulate such a device a number of ways more or less but can one b=
e made based on fundamental physical principles so that it behaves very sim= ilar to a "reverse diode"(by which I do not mean a reverse biased diode... = so please do not conflate the two).
>=20 > Is there any simple reason why such a semiconductor based device can not =
exist? i.e., Is it possible to have a semiconductor device with an IV curve= that **looks** like I(V) =3D 1/V or 1/V^2? Probably not, but search on the tunnel diode, which does have a distinctly = kinky I(V) curve. http://en.wikipedia.org/wiki/Tunnel_diode You could even buy one. http://www.electronicsurplus.com/item/8168/ --=20 Bill Sloman, Nijmegen
wrote in message=20
news:f9e8d5ca-f76e-42ba-b64b-21a8397fdcbd@googlegroups.com...

> Is there a passive device similar to a diode that has low > impedance at 0 forward voltage and high impedance at > some larger voltage?
> e.g., flip the diode curve horizontally then center the knee > of the several hundred mV above 0V.
> One can emulate such a device a number of ways more or > less but can one be made based on fundamental physical > principles so that it behaves very similar to a "reverse diode" > (by which I do not mean a reverse biased diode... so please > do not conflate the two).
> Is there any simple reason why such a semiconductor based > device can not exist? i.e., Is it possible to have a semiconductor > device with an IV curve that **looks** like I(V) =3D 1/V or 1/V^2?
A PTC current limiting fuse acts something like this. Also a tungsten = lamp. If it does not need to be reversible a fuse would fit this definition. A tunnel diode may also be similar but it needs to be biased, and then = it=20 has negative resistance. Is there a proposed application for a device having this property? Paul=20
On 07/09/2012 07:14 AM, P E Schoen wrote:
> wrote in message > news:f9e8d5ca-f76e-42ba-b64b-21a8397fdcbd@googlegroups.com... > >> Is there a passive device similar to a diode that has low >> impedance at 0 forward voltage and high impedance at >> some larger voltage? > >> e.g., flip the diode curve horizontally then center the knee >> of the several hundred mV above 0V. > >> One can emulate such a device a number of ways more or >> less but can one be made based on fundamental physical >> principles so that it behaves very similar to a "reverse diode" >> (by which I do not mean a reverse biased diode... so please >> do not conflate the two). > >> Is there any simple reason why such a semiconductor based >> device can not exist? i.e., Is it possible to have a semiconductor >> device with an IV curve that **looks** like I(V) = 1/V or 1/V^2? > > A PTC current limiting fuse acts something like this. Also a tungsten lamp. > > If it does not need to be reversible a fuse would fit this definition. > > A tunnel diode may also be similar but it needs to be biased, and then > it has negative resistance. > > Is there a proposed application for a device having this property? > > Paul
Sure thing. A depletion FET with gate and source connected, or a classical two-terminal BJT current limiter. (Series pass transistor, base connected to collector via big R, sense transistor's BE connected across a sense resistor steals base current when the drop across the sense resistor reaches V_BE.) You can add foldback, so that the current decreases at increasing delta-V. 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 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
On Sun, 8 Jul 2012 22:11:05 -0700 (PDT), "jon.jukoba@gmail.com"
<jon.jukoba@gmail.com> wrote:

>Is there a passive device similar to a diode that has low impedance at 0 forward voltage and high impedance at some larger voltage? > >e.g., flip the diode curve horizontally then center the knee of the several hundred mV above 0V. > >One can emulate such a device a number of ways more or less but can one be made based on fundamental physical principles so that it behaves very similar to a "reverse diode"(by which I do not mean a reverse biased diode... so please do not conflate the two). > >Is there any simple reason why such a semiconductor based device can not exist? i.e., Is it possible to have a semiconductor device with an IV curve that **looks** like I(V) = 1/V or 1/V^2? >
http://www.analog-innovations.com/SED/PerfectDiodeForChargerIsolation.pdf ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
jon.jukoba@gmail.com wrote:
> Is there a passive device similar to a diode that has low impedance at 0 forward voltage and high impedance at some larger voltage? > > e.g., flip the diode curve horizontally then center the knee of the several hundred mV above 0V. > > One can emulate such a device a number of ways more or less but can one be made based on fundamental physical principles so that it behaves very similar to a "reverse diode"(by which I do not mean a reverse biased diode... so please do not conflate the two). > > Is there any simple reason why such a semiconductor based device can not exist? i.e., Is it possible to have a semiconductor device with an IV curve that **looks** like I(V) = 1/V or 1/V^2? > >
If you are not too picky about voltages, an Esaki diode has low Z at and near 0V, and then the Z increases at the valley...