Anish Aaryan

A diode is an electrical device which allows the current to move through it in one direction easily than in other direction. The junction diode is the combination of p-type and n-type semiconductor material. The lead which is connected to the p-type material is called the anode and the lead which is connected to the n-type material is called cathode. The cathode is marked by a solid line of the diode.

Fig.1 Symbol for junction diode

When p-type of the material is connected to the positive side of the battery and n-type is connected to the negative terminal, then the current flow in the circuit. Such combination of junction diode and the battery is called forward-biased. When the polarity of the battery is reversed i.e. the p-type is connected to the negative terminal of the battery and the n-type is connected to the positive terminal, then the combination is called reversed biased. In the forward biased, holes in the p-type of the material are repelled by the positive terminal of the battery and so as by negative terminal and the electrons in the n-type material. This results in the decrease in the depletion layer and hence the current flow in the circuit. But, in case of the reverse-biased, there is increase in depletion layer and the diode blocks current. The diode is assumed to be closed switch for forward-biased and open switch for reverse-biased.




CIRCUIT DIAGRAMS: -



PROCEDURE: -
Forward biasing: -

1. Connect the circuit as shown in circuit diagram.
   
2. After connection the circuit, the power supply is varied from 0V to 2V by 0.1V.
   
3. Then, the voltage across the resistor and diode is noted.
   
4. Then, the circuit flowing across the diode is calculated.
   

 

Reverse biasing: -

1. Connect the circuit as shown in circuit diagram.
   
2. After connection the circuit, the power supply is varied from 0V to 20V by 1V.
   
3. Then, the voltage across the resistor and diode is noted.
   
4. Then, the circuit flowing across the diode is calculated.
   

 

The Hartley oscillator is an LC electronic oscillator that derives its feedback from a tapped coil in parallel with a capacitor (the tank circuit). Although there is no requirement for there to be mutual coupling between the two coil segments, the circuit is usually implemented as such. A Hartley oscillator is essentially any configuration that uses a pair of series-connected coils and a single capacitor.


Fig:Transistor Hartley oscillator


In the oscillator, the feedback voltage is developed by the inductive voltage divider, L1 & L2. Since the output voltage appears across L1 and the feedback voltage across L2, the feedback fraction is
β = V / Vout = XL2 / XL1 = L2 / L1
As usual, the loading effect of the base is ignored. For oscillations to start, the voltage gain must be greater than 1/ β. The frequency of oscillation is given by
f=1/(2π√(L_eq C))
Similarly, an opamp based Hartley oscillator circuit is shown below:



Fig: Op amp Hartler Oscillator

Haiku is a poetic form and a type of poetry from the Japanese culture. Haiku combines form, content, and language in a meaningful, yet compact form. Haiku themes include nature, feelings, or experiences. Usually simple words and grammar are used in Haiku. A Haiku must "paint" a mental image in the reader's mind.

The most common form for Haiku is three short lines. The first line usually contains five (5) syllables, the second line seven (7) syllables, and the third line contains five (5) syllables. Haiku doesn't rhyme.

This is the challenge of Haiku - to put the poem's meaning and imagery in the reader's mind in ONLY 17 syllables over just three (3) lines of poetry!

Previously called hokku, it was given its current name, Haiku, by the Japanese writer Masaoka Shiki at the end of 19th century.
Masaoka Shiki was the pen-name of a Japanese author, poet, literary critic, and journalist in Meiji period Japan. His real name was Masaoka Tsunenori, but as a child he was called Tokoronosuke.Later, he changed his own name Noboru.

Instruction to write Haiku:-
1. Think about a theme for your haiku and write down some of the words that come to mind on that theme.

2. Organize your thoughts roughly onto three lines. First, set the scene, then expand on that by expressing a feeling, making an observation or recording an action. Keep it simple.

3. Polish your haiku into three lines, the first with five syllables, the second line with seven syllables and the third line with five syllables. It may take some time and substitution of words to make it fit.

Examples:


See?
So simple.
Try. Practise. And be a Haiku poet.