7805

desperadogear

New Member

• Feb 22, 2007

• #21

whats the solution for this overloading problem?

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Feb 22, 2007

• #22

For a start measure the current it takes from the 7805, first without the backlight, then with it.

 

ikalogic

Member

• Feb 22, 2007

• #23

i never actually done the calculations...but a project with 9V battery feeding a micro controller, an LCD with white backlight, and IR proximity sensor ABSOLUTLEY needed a heat sink...

 

desperadogear

New Member

• Feb 26, 2007

• #24

For a start measure the current it takes from the 7805, first without the backlight, then with it.

Click to expand...

im really sorry if i was late to follow up.i got current measurement as 600 mA..

 

audioguru

Well-Known Member

Most Helpful Member

• Feb 26, 2007

• #25

The 7805 can easily supply 600mA. I think its input from the unregulated supply drops lower than its minimum input of 7.5V.

 

Hero999

Banned

• Feb 28, 2007

• #26

Try adding a 4700:mu:F capacitor in parallel with the input to the regulator.

 

desperadogear

New Member

• Mar 1, 2007

• #27

will try it right away. was using 1000 uF