hey guys, I found a battery (power source) that has 10400mA, is 5 volts, with 2 outputs. one output is 1 amp, the second is 2 amps.
would I need to put some sort of limiter on this battery, or can I use it as is? or will it fry the nano?
thanks
Just because the battery can supply 1 or 2 amps it does not mean that it will supply that much current. The important thing is that the input voltage to the Nano is correct.
The Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source.
ok...so....if I have 5 volts (non regulated supply) the 6-20v unregulated pin will not work? the battery says, "5 volts" I am sure it is not regulated, however.....would not 5 volts in the un-regulated 5 volt pin give 5 volts? wouldn't it simply stabilize the 5 volt battery supply? would the regulator (built in) lessen the voltage?
Yes, the regulator will drop (lessen) the voltage.
There's no battery chemistry that gives an output of 5V. It is quite likely that there is already a regulator inside the battery housing. Or it's a 7.2V battery and it has been labelled by an optimistic engineer in China who gets paid less than a nickel per hour.
Are you able to measure the battery output?
If you are going to be playing around with electronics, it's a good idea to get a multimeter (if you don't already have one) so you can measure voltage and resistance (and maybe occasionally current*). If cost is an issue, you can find a little multimeter for 10 or $20, and it's better than nothing.
would I need to put some sort of limiter on this battery, or can I use it as is? or will it fry the nano?
If you take an electronics class, the 1st thing you learn is [u]Ohm's Law[/u], which describes the relationship between voltage, resistance, and current. (Higher voltage = higher current, or lower resistance = higher current). ...Resistance is the resistance to current flow.
You also need to know that most voltage sources are "constant voltage" (or approximately constant voltage). i.e., There is 120V or 240V at your wall socket, whither you have nothing plugged-in, a 10W light plugged-in, or a 100W light, or a 1200W toaster. The current depends on what you've got plugged in, and if you draw too much current, you blow a circuit breaker.
We usually don't know the resistance of whatever's plugged in**, but the important thing to know is that the current depends on the "load".
If you connect an LED (with the appropriate current limiting resistor) to a 12V car battery that's capable of 300 Amps, you'll just get the normal 20 milliamps or so required to light the LED. And, you'd use the same resistor with a little 12V wall-wart power supply. (Without the current limiting resistor, you'll fry the LED, but that's the nature of LEDs...)
- We don't actually measure current that often. Current is a little tricky to measure because you have to break the circuit and insert the meter in series. And if you don't connect it correctly (with a circuit or "something" in series to limit the current), you can blow the meter's fuse.
** If you know the wattage of a light bulb (or whatever), and you know it's rated voltage, you can calculate the resistance and the current.