09-30-2020 05:23 PM
I have a power adapter for a Cisco 7912 phone that runs at 48V 0.38A and I would like to know if it would work with a 7940 phone which uses 48V at 0.2A. Thanks
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09-30-2020 05:42 PM - edited 09-30-2020 10:29 PM
After a while of research, I found this
Many people are confused by amperage ratings and what they mean when it comes to power supplies and replacements.
The amperage rating is the maximum amount of power it can supply.
One way to look at it is as if amperage were “taken” (often referred to as “drawn”, as in pulling) by the device being powered. That device will only draw as much amperage as it needs to perform whatever it’s doing. Your computer will use more power, in the form of higher amperage draw, when it’s working hard than when it’s not. (Voltage remains the same regardless.)
Thus, as long as you replace your power supply with one capable of providing as much or more amps than the previous supply, you’ll be fine.
If for some reason your replacement power supply has a lower-than-required maximum amperage rating, you may end up with a burnt out or overheating power supply, and the device itself may not function.
EDIT: So what this means is that in my case, because the phone is only going to draw 0.2A out of the 0.38A, it will be fine but if I were to use a 0.2A power supply on a 0.38A device, there would be issues.
09-30-2020 05:42 PM - edited 09-30-2020 10:29 PM
After a while of research, I found this
Many people are confused by amperage ratings and what they mean when it comes to power supplies and replacements.
The amperage rating is the maximum amount of power it can supply.
One way to look at it is as if amperage were “taken” (often referred to as “drawn”, as in pulling) by the device being powered. That device will only draw as much amperage as it needs to perform whatever it’s doing. Your computer will use more power, in the form of higher amperage draw, when it’s working hard than when it’s not. (Voltage remains the same regardless.)
Thus, as long as you replace your power supply with one capable of providing as much or more amps than the previous supply, you’ll be fine.
If for some reason your replacement power supply has a lower-than-required maximum amperage rating, you may end up with a burnt out or overheating power supply, and the device itself may not function.
EDIT: So what this means is that in my case, because the phone is only going to draw 0.2A out of the 0.38A, it will be fine but if I were to use a 0.2A power supply on a 0.38A device, there would be issues.
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