Can I use a 3 amp power supply?

You should be just fine with a 3A supply, as that is only 500mA over the maximum amount the Pi3B+ can draw.

Can I use 12V 3A for 12V 2A?

Yes. The 3A is the maximum current it can supply but it works fine delivering less current. For example, when this adapter is plugged but not connected to your device the current is zero but the voltage is 12V.

Is it OK to use a higher amp power supply?

A power supply with more Amps than required will not harm your router. It will only draw what it needs. If your router needs 2 Amps and your power supply provides 5 Amps, no problem. A power supply with more voltage than you need will however smoke your device.

Can I use A 12V 1.5 A power adapter on 12V 2A device?

Yes, there will be no problem. As long as the voltage of 12 Volts is same, it will work perfectly fine on a 12 Volt 1 Amp power supply as it would on a 12 Volt 0.17 Amp power supply.

Will too much amperage hurt A device?

A higher voltage than a device is designed for will most likely blow up some components, but amperage is derived from how much current is actually drawn, based on the device’s resistance, so having “too much” is not a problem and will do no harm.

Can I use A different power Adaptor?

You can safely use an adapter with the same output voltage, and a current (A/mA) rating equal or higher than the original. If you use one with significantly more voltage (and 12v is a full third more than 9v) then you might burn out your device.

Can I use A power adapter with less amps?

The amperage rating of a charger or power supply is the maximum it can supply. A device being charged will only take as much amperage as it requires. If your device needs 0.5 amps to charge, and your charger is rated at 1.0 amps, only 0.5 amps will be used.

Is it safe to use a 2 amp power supply?

Yes, with caution. 2A is quite a bit more (as opposed to a -LOT- more, like, say, 20A would be) than 0.8A. You device might not even have bothered with a proper fuse, thinking ‘oh well, the power supply will limit to 0.8 A’.

What happens if you use an incompatible power adapter?

If you grab an incompatible power adapter, your best case scenario is that it works, albeit not the way the manufacturer intended. The second worst-case scenario is that you fry the gadget you are trying to power up. The worst-case scenario is that you burn down your house.

What is the difference between a 5A and 8A power adapter?

For example, your laptop may be rated for an 8A draw, but in reality, it only draws around 5A. Conversely, an adapter may be rated at 5A, but can withstand currents up to 8A. Also, some adapters and devices will have voltage and current switching or detecting features that will adjust the output/draw depending on what’s needed.

What happens if there is too much power in an adapter?

Too much power generates excess heat, which is the bane of sensitive electronics. The other important term to know is polarity. There is a positive pole (+) and a negative pole (-). For an adapter to work, the positive plug must mate with a negative receptacle or vice versa.