[SOLVED] about voltage regulator circuit regarding.....

[PRABAKARDEVA]

what is the output for the circuit attached here?any explain it pls.....what is the fun of the diode as feedback to the voltage regulator?what should be happening regulator is connected to ground via diode?explain it pl ss..

 

[barry]

That diode is in backwards(the one across the regulator). Your output voltage will be Vin-Vdiode, the regulator does nothing, the other diode does nothing..

 

[Audioguru]

The diode at the top is backwards and is not needed.
The diode to ground raises the output voltage of the 7805 regulator to 5.7V.

 

[albbg]

If you reverse the polarity of the diode across the regulator it has the function to protect the regulator itself against the reverse current. If that diode is not present, the output capacitor could discharge through the regulator, so that the current will flows from the output towards the input of the regulator an can damage it. Usually this protection isn't really needed since the Vout-Vin is no high enough to damage the component since the capacitor will start to discharge toward the load.
I noticed that you supply the regulator by means an AC generator. I suppose it's a DC generator with superimposed a sinwave simulating the ripple in output of a Graetz bridge.

 

[pradeep.g.belchada]

first off all d1 is not needed it will pass the vin as vout. 12v is vin then vout will be 11v. in this case 7805 will not give 5.5v

 

[PRABAKARDEVA]

Thanks to you

can you explain y the regulator does nothing in this circuit?

 

[Venkadesh_M]

because the regulator is bypassed by the parallel diode.............

 

[PRABAKARDEVA]

can u explain about bypass?

 

[Venkadesh_M]

The Ic regulator only works in the positive cycle...

the Diode on the top of it also conducts in positive cycle so the current will not go through the Regulator and it will go through the diode....

 

[PRABAKARDEVA]

thank u venkadesh