LM7815 voltage regulator

A

adrian sphank

New Member
C1 = 470uf
C2 = C3 = C5 =0.1uf
C4 = C6 = 100uf
R1 =R2 =IK
Transformer = 9v – 0 – 9v
REG 1 = LM7812
REG 2 = LM7805

Circuit attach will produce 12v and 5v at the output.
How do I change this circuit to get a 15v and 5v at the output?

I know that LM7815 voltage regulator will produce 15v at the output. But how do I implement LM7815 to this circuit?
 

hi,
No circuit visible.
 
Must be typo

How do you get 12v from a 9v transformer mush less the 15v you want??
I am pretty the regulator needs more voltage. I recall 2-3 volts above desired voltage??
 
The 9V-0-9V transformer has a peak of 12.7V and the rectifiers reduce it to 12.0V. Ripple from the small filter capacitor reduces it further.

But the original LM7812 needs to have a minimum input of 15V.
Therefore the original circuit will not work.
 
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