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utkarshjain
03-08-2010, 07:45 PM
i prepared a line follower robot and was using lithium ion battery for testing...when i switched to battery eliminator the voltage instead of being +5v as output from 7805 power supply is +4.70v and it changes as the sensors sense or do not sense...generally it increases to +5v when sensors sense(all 2 sensors) and +4.70v when no sensors senses...what is the problem??i hav used capacitors arrangement with 7805...

rao
03-08-2010, 07:55 PM
What is the input voltage that you are providing to the 7805?

utkarshjain
03-08-2010, 08:02 PM
>6v...i even gave 11.5v

rao
03-08-2010, 08:24 PM
Make sure you always keep the input voltage above the minimum required Vin which is 7-8V for 7805. Also if you refer to the datasheet, the Vout at 10V Vin ranges from 4.8V to 5.2V so I don't think there is any problem.

Rao

utkarshjain
03-08-2010, 08:37 PM
can my micro controller AT89s52 run correctly for range 4.5v-5.1v

rao
03-08-2010, 08:41 PM
Once again, the datasheet says,

"4.0V to 5.5V Operating Range"

You need to start reading datasheets a lot. They really do have stuff worth knowing. You will become a lot more self-dependent.

Rao