Hi,

Recently I moved to a new apartment. Today, people from internet company visited my apartment for internet instalation. Since I lost my modem's original adapter (which was 12V1A) I used my spare adapter (12V2A) to power my modem. Person who did the installation told me to get a 12V1A adapter because my 12V2A adapter might burn the modem. I think he is mistaken, but I want to verify.

According to my understanding, amper ratings on adapters indicates how much current an adapter can provide before overheating becomes a problem. Since modem draw 1A under 12V, neither modem nor adapter should have a problem. Am I right?

 

hi YA,
A 12Vdc 2Amp regulated power supply will not cause a problem, the Modem will only draw the current it requires to operate.
E

 

Person who did the installation told me to get a 12V1A adapter because my 12V2A adapter might burn the modem. I think he is mistaken, but I want to verify.

Yes, he is mistaken.

According to my understanding, amper ratings on adapters indicates how much current an adapter can provide before overheating becomes a problem. Since modem draw 1A under 12V, neither modem nor adapter should have a problem. Am I right?

Yes, that's correct.

 

Recently had a doctor tell me to use the charger that came with my hearingaids. Said using a stronger one will melt the unit. I know that to be untrue. Same 5V charger. As long as the voltage is correct and the supply is sufficient there will be no problem.

Your car has a battery capable of producing hundreds of amps, yet your car radio that probably uses two amps doesn't burn up. So, as you know, and has been confirmed, using the bigger supply will not harm anything. Not unless you dead short it. Then you have a 2A short. Which will probably hurt the supply.

 

I think he is mistaken, but I want to verify.

That's a common misconception. Technicians don't necessarily know much about things they install.

EDIT: Changed doctor to technician; had Tonyr's doctor in mind while I was responding.

 

The only place I can think of where using a higher available amperage charger is when charging batteries. Some batteries like Li-Po's or Li-Ion require strict control of how the batteries are charged. Putting a stronger charger on them might exceed the ability of the charger to control the charge current going into the battery(ies) under such circumstances. But a router that doesn't have batteries to charge will be fine using a bigger supply (amperage wise).

 

Person who did the installation told me to get a 12V1A adapter because my 12V2A adapter might burn the modem. I think he is mistaken, but I want to verify.

You would be correct in that regardless of supply capability exceeding the load the load will only draw what it requires.

Ron

 

Short answer, voltage-yes, amperage-no. Never supply a higher voltage. The device will only draw the current it needs to operate.