What capacitor should I use

This is my first post and I am a beginner with Arduino so if I say something wrong I apoligize.

I am using the nRF24L01+ modules to communicate between 2 arduinos but I cant make it work. After a few hours I discovered I should use a capacitor to make the 3.3 V be more constant.

In this page they say I should use a capacitor from 3.3 uF to 10 uF.

https://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo

But I went to an online eletronic store of my region and when I type capacitor there are many types. Which one should I buy? Ceramic? Eletrolitic? I know those capacitors have special use cases, which one should be better to my case (keeping voltage while using too much current)?

If you could post me a picture of the capacitor I would appreciate cause if would make it easier to me identify the capacitor in the eletronic store.

I use 10uF electrolytics with nRF24l01+ with no problems. Picture attached.

tenuf.jpg

Ceramic or electrolytic. Ceramics are more cost-effective nowadays for that sort of thing.

Generally...

Ceramic's are the cheapest, but they cap out at 100uf, and are scarce above 10. You must use ceramics for bypassing (the ~0.1uf cap you need next to each IC). Now that they're available in such large values, they're practical to use for filtering too - but some voltage regulators aren't stable with ceramic caps (this is specified in the datasheet). These are typically your go-to for low value capacitors.

Electrolytics are available in larger sizes and for higher voltages than ceramics, and if you need a large (high value) capacitor, they're often your only choice. They are polarized, and have inferior reliability compared to ceramics. Traditionally used for power supply filtering, these are typically your go-to for higher values.

Tantalum caps are smaller than an electrolytic of similar size, with lower ESR as well, but are usually much more expensive. Advanced ceramic caps are encroaching on the traditional use cases for tant's - in the past, tant's were commonly used for bypassing. They are still widely used for power supply filtering and bypassing in portable devices. When these fail, they can smoke, catch fire, or explode - though if the manufacturer recommendations are followed, this is a very uncommon event. Polarized - fails catastrophically if polarity reversed.

Mylar/etc - Non-polarized caps available in higher voltages than ceramics are. Bulky and expensive - to be used only when other types don't meet the requirements of your project.

Ceramic and electrolytic capacitor assortments are available on ebay for stunningly low prices:

http://www.ebay.com/sch/i.html?_nkw=capacitor+assortment

DrAzzy: some voltage regulators aren't stable with ceramic caps (this is specified in the datasheet).

Care to elaborate on that, or do you just mean they require more than 10 µF?

@DrAzzy thanks for complete explanation and @RogerRowland thanks for picture. I will buy an eletrolitic as you said.

Paul__B: Care to elaborate on that, or do you just mean they require more than 10 µF?

He did mean what he said. The classic example would be the LM1117; it needs an ESR for the output cap between .3R to 22R which is much higher than typical ceramics.