Yes - what matters is the voltage - it has to be the same. The device will only draws 1A as needed - the adaptor with higher amp,i.e, 2A is fine. As long as the adaptor has amps equal to or greater than those of the device, it will be ok!
It is generally safe to run a 4.3V device with a 5V power adapter, as the device should only draw the amount of voltage it is designed for. However, there is a slight risk of damaging the device if the voltage is consistently higher than the recommended level.
USB 1.1 port (5V power) current is limited to 500mA.
No. In general, a charger needs to be able to figure out when the battery has reached full charge, otherwise the charger can damage the battery by overcharging it. You need to use the specific charger required for the battery. And, if you are trying to power a non-battery device that requires 1A from a 5V 100mA source, you will not be able to maintain 5V, so it will not work there either.
No, underpowering will not "power" the device, it will not run. You must get an adapter that is 6V and (2A or higher) will be ok as well.
A: Most LED needs a minimum voltage and minimum current in the right direction positive anode negative cathode to light up. Unfortunately the voltage can be as low as 1.2 to 5v and the same apply to the current from 5ma to 500ma. So there is no set values it depends on the device.
A: Most LED needs a minimum voltage and minimum current in the right direction positive anode negative cathode to light up. Unfortunately the voltage can be as low as 1.2 to 5v and the same apply to the current from 5ma to 500ma. So there is no set values it depends on the device.
No... the source does not have the required capacity. The device (sink) would ask for more current which the source will not be able to provide. Do not use this source-sink pair.
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Yes a 3.7v or 7.4v li-po battery can power a 5v device without spoiling it because P=IV.
If wired correctly, this will not damage the fan or the USB port, as the fan will take less current at a lower voltage. The main problem with this arrangement is the fan would either not start, or would run very slowly, so probably useless for cooling anything. If you can get a 5V fan, not more than 500mA, this would be much more effective. (Note- If wired incorrectly, reverse polarity could damage both USB port and fan, short circuit could damage your USB port.)
A zener diode has a voltage when it reachesbreak over it may be 5v 12vor other voltage as manufactured. The manufacture will produce a 5v zener or is it? This voltage can change from device to device but the mean or nominal voltage will be as close as 5v as possible. So when buying a 5v zener do not expect 5v absolute but a nominal 5 v ZENERS are designed for a specific voltage [ THEREFORE NOMINAL] as mentioned above . depends on the voltage required it can be bought within a specific voltage -/+ a % of the breakdown