Diffrentiate Between ACTIVE DEVICE and PASSIVE DEVICE...

[webscatter]

Kya nga ....lots of debates kung ang diode ba ay active or passive...

I still hold on Diode is active...
[Improve]  

A Device is said to be active if...

(i) It is a source of Power in the circuit...

(ii) It amplifies any voltage or current in a circuit...

(iii) It acts as a switch ie., has modes equivalent to ON and OFF...

e.g., transistor amplifies and can also act as a switch...


Not all info nakuha ntin sa net...ay 100% tama....kaya nga mga british...they are not relying on the net...they are still acknowledging the PUBLISHED articles and BOOKs....

http://www.freshpatents.com/Active-solid-state-devices--e-g--transistors-solid-state-diodes--dtnewntc257.php

Merong patent application p nga mention about the active category ng diode....CHECK sa USPTO articles...

Active solid-state devices (e.g., transistors, solid-state diodes)
Recently published patent applications awaiting approval from the USPTO. Recent week's RSS XML file available below.
Listing format for abstract view: USPTO application #, Title, Abstract excerpt,Patent Agent. Listing format for list view: USPTO National Class full category number, title of the patent application.

[rdpzycho]

^ sir I quoted 2 books right before your post. Paul Horowitz's Art of Electronics, and Donald Fink's Electronics Engineers' Handbook, with the exact page numbers.

Art of Electronics - http://books.google.com/books?id=bkOMDgwFA28C&lpg=PP1&pg=PA44#v=onepage&q&f=false

the formal definition with equation provided in Wikipedia is also co-authored by the Fil-Am Leon Chua who first formulated the theory of Memristors.

Wyatt Jr., John L.; Chua, Leon O.; Gannett, Joel W.; Göknar, Izzet C.; Green, Douglas N. (January 1981). "Energy Concepts in the State-Space Theory of Nonlinear n-Ports: Part I—Passivity". IEEE Transactions on Circuits and Systems CAS-28 (1): 48–61


the Application Note published by TI also include diodes as Passive Devices in Understanding Basic Analog - Passive Devices

http://focus.ti.com/lit/an/sloa027/sloa027.pdf


an MIT review note:
DIODES - Passive devices that only pass current in one direction

http://www.mit.edu/~godoy/6098/study/review4_diode_mosfet.pdf


a Dissertation by Ali M. Niknejad for Ph. D at Berkeley:

Typical examples of passive devices include linear time-invariant resistors of finite resistance R > 0 which dissipate energy, ideal time-invariant linear capacitors and inductors, which only store energy. While the above elements are linear elements, passive elements such as diodes can be non-linear. Even though passive devices can have voltage or current gain, they cannot have power gain.

http://rfic.eecs.berkeley.edu/~niknejad/pdf/NiknejadPhD.pdf


if we are to acknowledge Published materials and Books then can we quote the reference of this criteria:

A Device is said to be active if...

(i) It is a source of Power in the circuit...

(ii) It amplifies any voltage or current in a circuit...

(iii) It acts as a switch ie., has modes equivalent to ON and OFF...

[danny]

for me diode is passive
coz it doesn't need power or other
energy source for their operation
but i could be wrong, I always thought its an
active device

[tony]

in my book diodes are active devices...

[danny]

hay ang gulo ano ba talaga hehehe
 

[e.novacek]

well, we grew up in college thinking really that diodes are really an active devices and it doesn't exhibits the property of being a passive device.. in personal level, without this particular thread.. it seems that most of us still are carrying the idea that diodes are merely a device of active..

diodes are special case.. it can act as active device at some point.. and passive device to another point.. it only depends on whether it is used.. as active or passive applications.

just like the "light" on which it has dual characteristics.. as "wave" as it was stated in electromagnetic theory or "particle" as stated in optics theory..

upon my own definition of active device.. it is "voltage or current controlled" but not "direction controlled" of which conventional diodes does not exhibits this property.. under normal circumstance, diodes passes only forward current and blocks reverse current, or it passes AC and blocks DC. It also has the characteristics of power consumer just like with the case of resistor and not as power generator.

diodes (in the above case).. didn't alter the gain nor did *amplify a signal (*under normal condition) hence, it is a good example of a passive rectifier.. in contrast with active rectifier just like FET's..

but if in case that diode can be used as switching or voltage multiplier.. then diode meets the criteria of being an "active" device because switching is a good case of controlling flow of electrons.. good examples are SCR's, BJT's, FET's, and even vacuum tubes do exhibits this property.

voltage multiplication and biasing activities considers the conventional diode as "active device"

likewise, some diodes exhibits "non-linearity characteristics" the varactor diodes are "voltage-controlled" type of diodes hence, it falls under the category of active device..

[rdpzycho]

but if in case that diode can be used as switching or voltage multiplier.. then diode meets the criteria of being an "active" device because switching is a good case of controlling flow of electrons.. good examples are SCR's, BJT's, FET's, and even vacuum tubes do exhibits this property.

actually sir, voltage multiplication still wouldn't imply an active device since a transformer, which is also passive, can also multiply voltage, but divide current. hence, no power gain.

also switching may not imply activity, as diode mixers (which also uses the concept of switching diodes by the LO to mix the RF) are considered passive devices in Microwave. diodes are passive mixers, and gilbert cells will be active mixers.

as inferred on what Wyatt, Chua, et. al. stated in an IEEE transaction about Passivity (as posted on Wikipedia), as long as only the signal in concern passes through the device, it's passive. kapag may additional source na to control the device, it's active. like a tunnel diode which can be used as an amplifier in its negative resistance region, will be an active device.

[rdpzycho]

reference about passive and active mixers.

http://www.mhprofessional.com/downloads/products/0071544526/SayreCh07.pdf

[tony]

kapag may additional source na to control the device, it's active.

the reason i vote for diodes as being active is simple, you need to exceed it's threshold voltage to conduct current in forward direction, and to exceed breakdown voltage in the reverse direction......

now how many passive devices have this characteristics? raise your hand if you know of one....

what? i see none, therefore diodes are active devices, period...

[webscatter]

Look at the Characteristics of Passive Devices...

Resistor:

R is proportional to the voltage and varies inversely to the current

Capacitor:

C is proportional to the charge and varies as the voltage

Inductor (SELF-L)

L is proportional to the induced voltage and varies to the rate of flux

Tranformers (Mutual-L)

Mutual L is proportional to the alternating current  of one winding that tend to induce a voltage to the other.

Diode
Diode- Did not possess any of these properties.....

I still hold that diode is ACTIVE....

Forward current of the diode is approximated to:

Id = 26mV / Rd

Rd is the effect of "trans" resistance between the P and N Junction...

It's very clear that DIODE is active....

[webscatter]

How surprisingly nowadays....Diode is passive?

In the beginning, we are taught that DIODE is Active....

Kahit si BOYLESTAD nagsabi na ang diode is active...

[rdpzycho]

How surprisingly nowadays....Diode is passive?

In the beginning, we are taught that DIODE is Active....

Kahit si BOYLESTAD nagsabi na ang diode is active...

nowadays? Art of Electronics was published in 1989. Electronics Engineers' Handbook was published in 1975. Boylestad's book was first published in 1992, IIRC.

BTW, I was never able to find diode as active in a quick search of Boylestad's book. I may have skipped it by just typing on Acrobat's search.

Wyatt Jr., John L.; Chua, Leon O.; Gannett, Joel W.; Göknar, Izzet C.; Green, Douglas N. (January 1981). "Energy Concepts in the State-Space Theory of Nonlinear n-Ports: Part I—Passivity". IEEE Transactions on Circuits and Systems CAS-28 (1): 48–61.

published 1981. it was accepted as an IEEE Transaction, hence, this was criticized by their peers that time.


let us first define passivity and activity to get a clearer picture. medyo mahirap kasi kung by comparison lang.

if we can quote formal definitions and not just our opinions then we can really get a clearer picture of what will be active and passive.

the reason i vote for diodes as being active is simple, you need to exceed it's threshold voltage to conduct current in forward direction, and to exceed breakdown voltage in the reverse direction......

now how many passive devices have this characteristics? raise your hand if you know of one....

what? i see none, therefore diodes are active devices, period...

in transformer hysteresis, hence there is loss. to drive back the magnetic curve, a certain amount of magnetic field is needed, the core's coercivity. it may be argued that it's not a threshold to drive the transformer to conduct forward current, but it's a threshold needed to drive the transformer back, and we're not using transformers to be driven only in one direction.

[webscatter]

IF the diode is not an electrical equivalent of a switch....I will still stand that this device is ACTIVE...  :-)

A passive device is a device that "passes" a signal through or possibly alters the impedance of the signal but "passes" it through. A general rule is if it doesn't require power to work, then it is passive. Baluns are passive devices that change a balanced signal to an unbalanced signal (see Balanced & Unbalanced Signals for an explanation of Balanced and Unbalanced). Passive hubs typically contain only resistors between the ports. Almost all cables and cable adapters are considered "passive", typically all they're made of is wire and plugs. A user will typically look for a "passive" device to suit their needs, because passive devices are cheaper. But in some cases, we may have no choice but to go "active" to suit their needs.
An active device translates or strengthens the signal. As a rule, these need power to work. The Parallel Extender may appear to be passive because it runs without a power supply. But it is really an active device, pulling the power it needs from the handshake signals on the printer. In some cases, where the printer can't give enough power to it, the Parallel Extender will need an external power supply. To connect a Computer's serial port to a parallel printer requires an active device, the serial to parallel converter. Also, converting the PS/2 style keyboard to USB requires an active device, the USB to keyboard (and mouse) converter.
With SCSI Terminators, a passive terminator contains only resistors. The passive terminator works with low to medium speed SCSI signals, but there are some SCSI circuits that the Passive terminator will not work on. An Active terminator contains a regulator for better precision, which is needed for higher speed SCSI signals. The LVD terminator is an Active terminator made for the LVD interface.

http://www.cabledepot.com/05DTACTPASS.html

[webscatter]

Diode alters signal...
Diode replicates a mechanical switch...
Diode needs power so that it will work...

That is why... it is active....


Rectification:
Vdc=2Vm/pi   (full-wave)

Vdc=DC signal

Vm=half of the AC signal(P-P)....

Logic:

Equivalent to a mechanical switch....by applying voltage logic....





 

[webscatter]

I am referring to PN junction diode or semicon diode....

:-)

[rdpzycho]

A general rule is if it doesn't require power to work, then it is passive.

Crystal Sets can let you listen to AM stations without the need for power. it's an antenna, a coil, a diode, and a capacitor. Crystal Sets were considered as Passive Receivers.

Flashing LED indicators can tell you if there's GSM transaction ongoing, also without the need for power (they cling fancily to cellular phones before). it'a a coil, a germanium or schottky diode, and an LED.

[rdpzycho]

Diode alters signal...

Inductors and Capacitors also alter signal.

pass a full wave rectified signal to a LC tank resonant to its frequency, output signal will then be full sine. this was our first experiment (years ago) in communications in Amplitude Modulation. it's also the resonance that's exploited by Class C amplifiers to increase efficiency.

pass a square wave signal to a high Q LC filter, output signal will also be sine. older DTMF decoders use such circuits.

Diode needs power so that it will work...

transformers also need extra power to magnetize and demagnetize its core. the power comes from the signal it passes through.

diodes also take the power necessary to overcome it's region from the signal it passes through.

some cellular phones also use passive mixers as they won't need additional power from the battery. the diodes get the power they need from the local oscillator. IIRC, it's either Nokia or Ericsson which patented the LC balancer in replacement of the transformer for the single balanced diode mixer.

[rdpzycho]

Diode replicates a mechanical switch...

a diode replicates a mechanical diode or a freewheeling hub in a bike. it allows rotation in one direction, but not the other. it doesn't require extra input aside from the rotation it must transmit. everything is done automatically by its design.

a mechanical switch will require user input and will not do its switching automatically, which the mechanical diode and the electrical diode does when given a stimulus.

[webscatter]

A general rule is if it doesn't require power to work, then it is passive.

Crystal Sets can let you listen to AM stations without the need for power. it's an antenna, a coil, a diode, and a capacitor. Crystal Sets were considered as Passive Receivers.

Flashing LED indicators can tell you if there's GSM transaction ongoing, also without the need for power (they cling fancily to cellular phones before). it'a a coil, a germanium or schottky diode, and an LED.

Guys......we do all know....power is there...

An indication of Light glow or illumination of the LED means there's a power source taken mutually....

impossible walang source...

We are Violating the POWER EFFICIENCY principle....Power IN=Power OUT

n= Po/Pi   ( n approaches 1, ideally but not practically)


Why there is a change of heart? na ang diode ay PASSIVE...

that since the invention of diode....ito na ay active talaga....

This is a not debate....we are only discussing a wild or hot issue....

:-)

[webscatter]

a diode replicates a mechanical diode or a freewheeling hub in a bike. it allows rotation in one direction, but not the other. it doesn't require extra input aside from the rotation it must transmit. everything is done automatically by its design.

a mechanical switch will require user input and will not do its switching automatically, which the mechanical diode and the electrical diode does when given a stimulus.

To ALL ECEs who knew that...

LOGIC ICs started from Diode logic...

DTL+RTL becomes TTL logic plus dagdagan p ntin ng TOTEM POLE Output....Standard TTL na

DTL OR + RTL becomes TTL NOR

DTL AND + RTL becomes TTL NAND

The Foundation of Standard TTL or 7400's started from this LOGIC...

The point here DIODE is clearly an ACTIVE Device....



"a diode replicates a mechanical diode or a freewheeling hub in a bike."



Diode.....Alteration occurs on Current variation....
With respect to current flow...
PASS DC, BLOCK AC     Id=Is x Exponential value  (Is=Saturation Current)


Capacitor and Coils ...Alteration occurs on Frequency variation....



Coils cant replicate a mechanical switch....


(Diode) not similar to RFCs:
With respect to frequency...
PASS DC, BLOCK RF AC    




Capacitor cant replicate a mechanical switch....

PASS AC, BLOCK DC....   C= Q/V