Working of Solar charger circuit

[NafeesAhmed]

Hello everyone !
can you please tell me how this whole circuit is working ?
specially these ones,

1.whats happening at LM317's pins(in adjust and out) ?
2. what's the purpose of zener here?
3. purpose of transistor nd how is it working ?

last question!
how much time it will take to charge that 6v(4.5Ah) battery if we use 12v(3watt) solar panel?

 

[davenn]

there's a full description on the www site where you got the circuit

what part of the description, specifically, didnt you understand ?

cheers
Dave

 

[NascentOxygen]

The homework sub-forum is the correct place for posting this question (or rather, these 4 questions).

 

[NafeesAhmed]

The homework sub-forum is the correct place for posting this question (or rather, these 4 questions).

LOL :D its not homework

 

[NafeesAhmed]

there's a full description on the www site where you got the circuit

what part of the description, specifically, didnt you understand ?

cheers
Dave

as far as i know to calculate output of lm 317 we use this equation
vout= 1.25*(1+R2/R1)
and in my case vout is 8.194v.
please tell me what about about the incoming voltage? why don't we consider that volatge in this equation? what if my inut voltage is around 8 volts? what would happen then?

 

[berkeman]

as far as i know to calculate output of lm 317 we use this equation
vout= 1.25*(1+R2/R1)
and in my case vout is 8.194v.
please tell me what about about the incoming voltage? why don't we consider that volatge in this equation? what if my inut voltage is around 8 volts? what would happen then?

Look on the datasheet for the minimum input-output differential voltage specification (sometimes called the "dropout" voltage).