AC to DC Wall Adapter:Vout 12Vdc Measured 19.5V?

In summary, the conversation discusses a potential discrepancy between the measured voltage and the intended voltage on an adapter. The possibility of measuring the RMS value is brought up and it is suggested that the output may have a lot of ripple, resulting in a higher voltage reading. It is also mentioned that the converter's output may have a lot of "droop" and the voltage values given are typically rated values at full load. It is advised to use the converter at its rated load to avoid any potential damage.
  • #1
david90
312
2
On the adapter, Vout is 12Vdc but when I measured it with a voltmeter it shows 19.5V. Is there a typo or does the voltage somehow drops down to 12V when in use with a load?
 
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  • #2
Are you sure you not measuring RMS value?

Vrms = Vo/sqrt(2)
 
  • #3
dduardo said:
Are you sure you not measuring RMS value?

Vrms = Vo/sqrt(2)

RMS?? The output is DC.
 
  • #4
The output probably has a lot of ripple. Your measuring meter is probably is seeing it.
If your meter can measure AC try it an see how much.
 
  • #5
I've seen this a lot of times. I think there must be a lot of "droop" in the converter's output. At rated load it's probably at stated voltage, but open circuit, it's high. I think if you should use these converters at their rated load. Load too high -- burn them out; load too low -- maybe damage your load.
 
  • #6
I agree. Most voltage values given are rated values at full load (i.e. rated current).
 

FAQ: AC to DC Wall Adapter:Vout 12Vdc Measured 19.5V?

What is the purpose of an AC to DC wall adapter?

An AC to DC wall adapter is used to convert the alternating current (AC) from a wall outlet into direct current (DC) that is suitable for powering electronic devices. This allows devices that require DC power, such as laptops, to be used with a standard AC outlet.

What does "Vout 12Vdc Measured 19.5V" mean?

"Vout" stands for output voltage, which in this case is 12 volts (Vdc). However, the adapter may actually measure a slightly higher output voltage of 19.5 volts due to factors such as voltage drop and efficiency. This is still within the acceptable range for most electronic devices, but it's important to check the voltage requirements of your specific device before using the adapter.

Can I use this adapter for any device that requires 12Vdc?

No, it's important to check the voltage and current requirements of your device before using any adapter. Using an adapter with the wrong output voltage could damage your device.

How do I know if this adapter is compatible with my device?

You can check the voltage and current requirements of your device and compare them to the output specifications of the adapter. It's also important to make sure the plug size and polarity (positive and negative) match your device.

Is it safe to leave this adapter plugged in when not in use?

It is generally safe to leave the adapter plugged in when not in use, but it's important to note that it will still consume a small amount of energy. It's recommended to unplug the adapter when not in use to save energy and prevent any potential hazards.

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