Why DIODE is a non linear device???

• Ideal Diode:

➝ We know that an Ideal Diode is work same as an Ideal switch as discussed earlier.

➝Ideal Diode does not consume or Absorb any power from the source it means it has zero internal resistance and power loss.

Fig(a) Symbol of an Ideal Diode

• DEFINITION:-

➝"An ideal diode is one type of electronic switch (Ideal Switch), it allows to pass the current in only one direction ( ANODE TO CATHODE)".

Fig(a) working of an Ideal Diode

✱ DURING POSITIVE HALF CYCLE OF AC SUPPLY:-

⇨During the positive half cycle of ac supply P (anode) terminal of diode is connected to the +Vin and N (cathode) terminal of diode is connected to the-Vin of ac supply, so diode is in forward bias and start conducting.

⇨During forward biasing of diode current I is start to increasing and flows through the load.

✱DURING NEGATIVE HALF CYCLE OF AC SUPPLY:-

⇨During the Negative half cycle of ac supply P (anode) terminal of diode is connected to the-Vin and N (cathode) terminal of diode is connected to the +Vin of ac supply, so diode is in reverse biase.

⇨We know that diode doesn't allow to flow current in reverse biase, so that whole Negative half cycle of ac supply is BLOCKED across the Diode.

Fig (c) waveform of given circuit

• From the waveform we clearly understand that during positive half cycle of ac supply output is changed with respect to input but during the negative half cycle of ac supply, output remain ZERO during whole Negative half cycle.

➝So, from the above discussion and waveform we conclude that AN DIODE IT SELF SOWS NON LINEARITY, it means output does not follow input.

             ................Thank you 🙂................

How PRACTICAL DIODE works???

• To understand the working of practical diode, first we need to know the difference between an IDEAL DIODE and PRACTICAL DIODE. 

• Difference between an Ideal Diode and Practical Diode.

1. An Ideal Diode is behaves same as an Ideal switch. There is zero voltage drop across it.
2. But Practical Diode is replaced by its cut-in Voltage.
3. An Ideal Diode doesn't consume any power from the source during its operations.
4. Practical diode consume some amount of power from the source.
5. Ideal diode is replaced by short circuit when it is forward bias whereas an practical diode is replaced by an cut-in Voltage when it is forward bias. 

❋PRACTICAL DIODE:-

⇨Practical diode is conducted if an only the supply voltage is greater than its cut-in Voltage.

"Cut-in Voltage is the minimum potential required for satisfactory conduction of diode is known as a cut-in Voltage".

Fig.(a) Symbol of Practical Diode

• Cut-in Voltage is denoted by =Vλ
• If diode is Made up if GERMANIUM = Vλ = 0.3 Volts
• If diode is Made up of SILICON = Vλ = 0.7 Volts.

Fig(b) Use of Practical Diode in Circuit

Fig(c) Out put waveform

❇️ DURING POSITIVE HALF CYCLE OF AC SUPPLY:-

• At t=0 ; the value of Vin = 0 volts so diode D doesn't conduct this state of diode is called as a FORWARD BLOCKING MODE, when Vin> 0.7 Volt (for silicon) at that time diode is start to conducting, this state of diode is called as a forward conduction mode. During forward conduction mode diode is replaced by short circuit and current start to flow from P to N terminal of diode, Load and Vin and output voltage is obtained across the load RL.

❇️ DURING NEGATIVE HALF CYCLE OF AC SUPPLY:-

• During Negative half cycle of ac supply P terminal of diode is connected to the -Vin and N terminal of diode is connected to the +Vin of ac supply so diode is reverse biase and out put voltage across the load is zero during whole Negative half cycle as shown in waveform.

☺V-I characteristics of an practical diode:-

Fig(d) I-V characteristics of an practical diode

Where;  Vλ = Cut-in Voltage

                I0. = Reverse saturation current

• Reverse saturation current:-

" It is current of diode which is flows due to the minority carriers".

            ...................Thank you 🙂.................

How Ideal Diode is work??

• IDEAL DIODE:-

Fig(a) Symbol of Diode

⇒An ideal diode is behaves same as an Ideal switch.

• Behaviour of an Ideal Switch: