help me creat a circut , reducing 9V dc to 5.1v dc and with currnt 0.7A

[charanbg90]

plz!! help me to creat a circut i.e, reducing 9V dc to 5.1v dc and with currnt 0.7A

dear sir,

i want to create a dc cell charger... so plz guide how to make stable circuit that has to reduce 9V dc (source) to 5.1V dc and with current 0.7A .. actually i took this value from my cell charge adopter's label .. !! if u guide me with theory ill be more thankful to u all

hope ill receive guidance
thinking you !!
charan

 

[Miguel Gaspar]

The principal aspect for a battery charger is the current, that is because the voltage in the different stages of charge will be diferent.
So you need a constant current source.
And you already have a 9Vdc. So you need the current. There are two ways to solve that.
Using the LM317 as a current source you can have a good information in the web page of onsemi. This is the very easy way.
The second is using a MOSFET, like the IRFD110, as a current source. Information is available everywhere the Vgs = 4.8322 will give you the Id=0.7 Amp.

 

[charanbg90]

a special thanks to u sir , ill try it !!