Basic confusion about the behaviour of diodes

[shaswat]

I have a very little doubt on the basics of a diode. After a small interval I found the answer but I don't know that I am correct or not. Here is where I stuck for 20 min

As diode starts conduction when the voltage across it is 0.7 volt (general condition). After studying piecewise linear model, the equivalent circuit of a diode can be replaced with the Ideal diode in series with the resistance and a threshold voltage 0.7 V.Now ,what is the meaning of that resistance??
I know as ideal diode is connected in series so resistance is responsible for the 0.7 v drop.

In practical if we consider a diode having forward current 10mA and forward voltage of 3.3V, then according to that model the average resistance(Rav) is

Rav= (3.3-0.7)/(10mA-0)

This results 260 Ohm. So is that 260 Ohm is responsible for the drop of 0.7V. I think, YES (correct me if I am wrong)

Now reverse of that, If I need a resistance of 260 ohm and instead of this if I connnect a diode, does it works as same as resistance (if V & I remains constant)???

 

[Murugesh_89]

What is meant by the diode having a forward voltage of 3.3V?
Can you give the circuit diagram including the supply voltage and drop across each component and what you want to achieve as per your last statement?

 

[shaswat]

What is meant by the diode having a forward voltage of 3.3V?
Can you give the circuit diagram including the supply voltage and drop across each component and what you want to achieve as per your last statement?

Means if I connect a 3.3 v battery across a diode.

Listen I didn't ask any tough question. I just ask a very basic question. No drops, no achievements and none other thing. I follow "Electronic Devices and Circuit Theory" boylestad. Section "Piecewise Linear Model"

 

[FvM]

"Piecewise linear" means you can't determine an equivalent series resistance value at 0.7 V and assume it's still valid at 3.3 V. According to the exponential I/V characteristic, you get the tenfold current when increasing the forward voltage by 0.06 V.

No usual silicon diode will stand a forward voltage of 3.3V longer than a few microseconds.

 

[shaswat]

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"Piecewise linear" means you can't determine an equivalent series resistance value at 0.7 V and assume it's still valid at 3.3 V. According to the exponential I/V characteristic, you get the tenfold current when increasing the forward voltage by 0.06 V.

No usual silicon diode will stand a forward voltage of 3.3V longer than a few microseconds.

Correct I agree with you. But if I connect it with a 3.3V / 10mA then the following things occurs.

1) Diode will conduct (definitely)
2)Now If I want to know the resistance of the diode means Rav then according to book

Rav= (3.3-0.7)/(10mA-0)
This gives 260 Ohm value.

So the diode at conduction mode equivalent to a 260 Ohm resistance (correct me if I am wrong)

Now if I replace a resistance from a circuit (260 ohm) with the diode at the same vol age current then is it works same or not??