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Originally Posted by hexibot43 Alright. In choosing the Caps to go with a 7805, and a 7809 where does one start? I've read a few peoples thoughts, and come to the conclusion I'd better get some more input. And the choice of Cap type? I've seen specs from 1000uF to 10uFs. Stating all electrolytic. Then someone else wrote that using strickly electrolytics could give rise to problems.
I am really trying to understand this, so any info would be helpful. Thanks, Marcello |
They aren't particularly critical about values, either small electrolytics (1uF to 10uF) or 'large' non-electrolytics (0.1uF to 0.47uF) all appear to work well. Something like a 1000uF is far too big, you often have one on the input side (as a reservoir capacitor), as well as a smaller capacitor for stability.
If you really want "belt and braces", use a 10uF and a 0.1uF in parallel on both input and output.
Remember, the stability capacitors MUST be as close as possible to the pins - if you check the hardware for my PIC tutorials I place them right next to the chip. Notice that I use small electrolytics on those boards!.