There are a wide variety of semiconductor diodes like  

PN Junction Diode ((IN4007 -  (Small one), DR25 - (Large one) )

DR 25 Clearly exhibits reverse charcateristics.

Zener Diode (pink color one) shown in Left top pic.

In the right top pic older vaccum tube diode is shown. 

In left bottom pic diode symbol with terminals a(anode), k(cathode) is shown. 

In the last figure current direction along with polarities is shown . 

Please observe ALL.

Sri 

Have you identified the scientist in the previous photo ...

He is also inventor of "Photophone "& "Metal detector"

He also extended his works to "Aeronautics" and "Eugenics" also.

Now at least you got some idea. 

I will give very simple clue his wife name is "Hello".

Dear students is none other than 

Alexander Graham Bell ...

He is the inventor of Telephone.

He given a big gift to his wife. He first talked to his wife named Hello with the telephone he invented. 

Hence first word that talked on telephone is Hello.

HENCE IT BECOME THE FIRST WISH ON TELEPHONE FOR EVERY BODY ...

ITS THE STORY BEHIND HELLO ...

ITS THE KNOWLEDGE WHICH CAN NOT APPEAR IN TEXT BOOKS ...

HOPE YOU GOT SOME THING FROM MY SIDE ... 

Thank you ...

 Next time i will discuss with some more good and curious things by making a tribute to graham bell. 

On his name we have bell laboratories.

          Salute Sir

HE ALWAYS SAYS

When one door closes another opens but we often look so long and so regretfully upon the closed door that we do not see the one which is open for us.

I was really inspired from this words from a decade  of years.

The meaning of this quotation in my view to all students is  : 

Students please see the opportunities which are opened don't think about already closed opportunities.

GO AHEAD …

ENTER INTO

YOUR DREAM UNIVERSITY

“WORK HARD UNTIL YOU FULLFILL YOUR DREAM”

Identify who is this famous scientist ?

Famous as : Father of Modern Telecommunications

There are a lot of good things to share about him. 

hence today i given 3 clues for finding him : quotation, photo, famous as.

If any body knows share the name. 

Later i discuss curious things about him. 

yours 

Sri