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Question about 7805 ~~~~~~

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No22Ben

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Well, I'm building a voltage regulator circuit which convert 12v to 5v ... the component that I use is the 7805 ( convert input voltage to 5v ) , do I need to use capacitor ??? or just 7805 already can complete the task ???8-O
 

You didn't mention if the input was DC or AC. The 7805 will only work with a DC input so if your 12V is AC you must rectify and filter it first.
In any case, you should always fit a capacitor across the regulator input and ground pins, as close as possible to the device itself. Manufacturers suggest different values but anything from about 1uF upward should be OK. It is advisable to add a second capacitor between the output and ground pins, again as close as possible but in most cases it isn't essential. If you leave the input capacitor off, there is a real danger of the 7805 oscillating by itself and it's output voltage would be completely unregulated. I have seen severe damage caused to equipment simply because one capacitor was left out!

Brian.
 

you must use capacitor both in front and after the regulator. Also you must use a electrolit capacitor hi vaule (10uF) and more na a low value parasitic capacitor( 100nf).
:)
 

The input and output pins of the regulator needs to be filtered for better performance. I usually use 1000/25V to the input whereas 100/25V to the output in all my circuits which works without any problems.
Cheers
 

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