A conversation with Sr. Embedded Engineer of Precision Electronics Limited

Yesterday my room mate's friend came to my flat, who is working at Precision Electronics Limited, Noida. I tried to know about what he actually does at his job as an embedded engineer. He told me that he deals with power supply.
Oh Jesus !!! I was thinking in my mind that I can also made power supply then what the hell he has extra which I don't have. Even though every mobile charger has a power supply circuit to convert AC to 5V DC (variation may be there).... Even though by using  7805 IC we can convert the supply to 5V DC......
I was feeling like hell.... and simaltaneously I was also feeling happy that I know it .. I can also approach his company.

Then I tried to know more about his job profile. He told me the fact that power supply doesn't mean ALL about converting into 5V. Generally 7805 gives 0.5-1.0 A current, but there are applications where we have to amplify the current to upto 18 A keeping 5V constant. There are applications where we can't allow the tollerance of even 0.1V.
I asked him, do you also use 7805 to have a constant 5V DC ? He replied, NO.... Oh Jesus !!! Again... now what the hell you do use.... ?
He answered that there are applications in which the operating enviornment of any circuit is even upto 150'C and 7805 can't tollerate this temperature.
Thanks to him to let me know the different aspect of Electronics. Life is not all about what we read? Life is all about what we debugg.......
"Debugging, Debugging and Debugging makes you a perfect engineer."