BIASING

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koley

Joined Mar 3, 2006
1
Could someone kindly help me with this assignment.


The diode current, i terms of voltaveV, is approximately given by
I=I.{exp(eV/kT)-1} where e=1.6^-19 coulomb is the electronic charge, k=1.38^-23joule k=boltzmann constant and T-temp. in K
if the saturation current I. is 1ηA, cal the forward and reverse resistances at V=0.2 and T=300K[/FONT]



Thanks a lot.
 

Papabravo

Joined Feb 24, 2006
13,472
Originally posted by koley@Mar 4 2006, 12:10 AM
Could someone kindly help me with this assignment.
The diode current, i terms of voltaveV, is approximately given by
I=I.{exp(eV/kT)-1} where e=1.6^-19 coulomb is the electronic charge, k=1.38^-23joule k=boltzmann constant and T-temp. in K
if the saturation current I. is 1ηA, cal the forward and reverse resistances at V=0.2 and T=300K[/FONT]

Thanks a lot.
[post=14623]Quoted post[/post]​
I'm going to assume that V(reverse) = -V(forward) = -0.2 Volts

So
R(forward) = V(forward)/I(forward) = +0.2/I(forward)
R(reverse) = V(reverse)/I(reverse) = -0.2/I(reverse)

does that help?

By the way is this a germanium diode?
 

windoze killa

Joined Feb 23, 2006
605
Originally posted by Papabravo@Mar 4 2006, 03:32 PM

By the way is this a germanium diode?
[post=14624]Quoted post[/post]​
Aren't germanium diodes dead and buried and pushing up daisies?????

Or should that be pushing up geraniums?????

Just some sick humour. Please forgive me and even ignore me.

Sorry. Couldn't resist.
 

Papabravo

Joined Feb 24, 2006
13,472
Originally posted by windoze killa@Mar 4 2006, 02:47 AM
Aren't germanium diodes dead and buried and pushing up daisies?????

Or should that be pushing up geraniums?????

Just some sick humour. Please forgive me and even ignore me.

Sorry. Couldn't resist.
[post=14631]Quoted post[/post]​
Apparently not
Germanium Diodes
 

beenthere

Joined Apr 20, 2004
15,819
Hi,

Just bought some 1N34's - you just never know when they'll come in handy. Might even save an oatmeal box and wind a coil some day.
 

aac

Joined Jun 13, 2005
35
Originally posted by koley@Mar 3 2006, 11:10 PM
Could someone kindly help me with this assignment.
The diode current, i terms of voltaveV, is approximately given by
I=I.{exp(eV/kT)-1} where e=1.6^-19 coulomb is the electronic charge, k=1.38^-23joule k=boltzmann constant and T-temp. in K
if the saturation current I. is 1ηA, cal the forward and reverse resistances at V=0.2 and T=300K[/FONT]

Thanks a lot.
[post=14623]Quoted post[/post]​
The small signal equivalent conductance can be found by taking the derivative of the current equation with respect to V.

dI.{exp(eV/kT)-1}/dV = I.{exp(eV/kT)}*(e/kT)

Just put .2 and -.2 in calculate the conductance and divide into 1 to get resistance.

Alternately you could start with

V = (kT/e)ln(I/I.+1)

and take the derivative with respect to current to get resistance directly.
 
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