Hey y'all, i have a question about the capacitors used in this schematics i found on the arduino site:
I was looking over electronics stores for the right capacitors for the job, and it turned out there are numerous types of 10uF and 100nF capacitors. Most of them have a voltage raging from usually about 50 till multiple thousands. I'm a total noob at electronics, i just want to have fun with programming the thing, so i have no clue what capacitors to get. I would imagine since the thing runs on 5 volts, it would be a good idea to find a 5V 100uF and 100nF capacitor, but either those don't exist, or the webshops i was looking at don't carry them...
So the actual question: can someone point me out which capacitors i need? :-[(damn i feel like an awefull noob...)
I would imagine since the thing runs on 5 volts, it would be a good idea to find a 5V 100uF and 100nF capacitor, but either those don't exist, or the webshops i was looking at don't carry them...
I'm a software guy pretending to know something about hardware but AFAIK the voltage rating on capacitors is the maximum voltage they can handle so you just want something that's higher than 5V. (There's probably some rule of thumb of how much higher you should allow but at 5 volts anything should do.) I'm not 100% percent sure at what point using "too high" values would cause problems--I assume it affects physical size mostly.
So the actual question: can someone point me out which capacitors i need?
My partially informed suggestion would a 50V rating should be fine. From a quick glance at the schematic I'm assuming those capacitors are used for power de-coupling. You might want to try looking it up.
i feel like an awefull noob...
Relax, you gotta start somewhere--being able to articulate your question, show some research and be polite like you have done is a good start and better than some!
The general rule is to get something rated higher than the voltage of the circuitry that the cap goes into. The higher rating is really a "safety margin", for higher voltages that might come along.
Small caps are easy to find with high voltage ratings. For small caps like .1UF ( i.e. 100n) I usually buy 50V or 63V units, which means I can use them in circuits up to about 40V or so safely, and have a margin for 'spikes' that come along. Small caps are easy for manufacturers to make at higher voltage ratings; 100n caps form Digikey are about 6 cents.
For larger electrolytic caps (usually used for power supply filtering), the safe rule is also to use a cap rated double the power supply voltage. So for a 5V supply where you want to put a 100uF cap, you would want a capacitor rated at least 10V. Voltage ratings come in standard sizes (6.3V, 12V, 25V, 50V, 63V...etc) so the logical closest one is 12V.... If you're using caps in a power supply that is regulated, then you can cut things a bit closer and use the 6.3V cap. Caps that go begfore the regulator, on the unregulated side of the power supply, should have ample safety margins.
i have a question about the capacitors used in this schematics i found on the arduino site:
