Hi Guys,

I have a few questions about capacitors.

1. Do bypass capacitors need to be directional/electrolytic?
2. When it is critical for a smooth input into a component, can I use as many capacitors as I need to cover the Hz range I need? Say for instance can I just pile on capacitors until I've covered 100KHz - 100MHz?
3. Which material that capacitors are made (including the isolation material between the plates) would be considered the longest lasting? In other words, do ceramic caps last longer than aluminium ones for instance?

Thanks a lot in advance!

 

At those frequencies, ceramic caps are very good. They are available in sizes that would not require you to pile a bunch of them in parallel, but you can do that if you want to.

 

Thanks #12!

 

It comes to a question of physical size. It used to be that anything over 1μF your only choice was electrolytic.

For best performance, you want to go with SMD caps. I have seen up to 10μ non-polarized SMD in reasonably small footprint.

It is common to put two or three caps in parallel, depending on the current and frequency conditions.

For most situations, 0.1μF and 10μF will cover most cases.

0.1μF and 4.7μF is also a good combo if you can't find 10μF in 0805 SMD.

10nF, 100nF and 1μF might be good for high frequencies.