Which Adapter Requires More Watts for My Device?

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Discussion Overview

The discussion revolves around determining the wattage requirements of two electrical adapters for a specific device, focusing on the conversion of voltage and current into power measurements. Participants explore the implications of using different voltage and current ratings for AC and DC connections.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant notes that wattage can be calculated using the formula Watt = Volt x Amp, but expresses difficulty in converting the units accurately.
  • Another participant states that 1 Volt multiplied by 1 mA equals 1 mWatt, suggesting a basic understanding of power calculations.
  • A participant calculates the power for the first adapter when connected to AC, yielding 4600 mW, and contrasts this with the power drawn when connected to 4 V DC, which is 600 mW, raising questions about the differing power requirements.
  • Concerns are raised about the implications of using different power ratings for the same appliance, with a mention of the power factor (cos phi) affecting AC power calculations.
  • One participant shares their context, explaining they are trying to use a European adapter in the USA, seeking advice on wattage and voltage conversion.
  • Another participant suggests that purchasing a suitable adapter from a shop would be a practical solution, while also noting the frequency difference between the US and Europe.
  • There is a suspicion expressed that the 4V DC and 120mA rating might represent the output specifications of the adapter.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the power ratings and the appropriate use of the adapters, indicating that there is no consensus on how to resolve the discrepancies in power requirements for the device.

Contextual Notes

Participants have not fully resolved the implications of using different voltage and current ratings, nor have they clarified the role of the power factor in AC power calculations. There is also uncertainty regarding the output specifications of the adapters.

Who May Find This Useful

This discussion may be of interest to individuals dealing with electrical adapters, particularly those transitioning between different voltage standards or seeking to understand power requirements for devices with varying specifications.

Latvian
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If I have 2 electrical adapters for a specific device, which has the following information on them:

1- 230va/50hz/20mA
4vdc/150mA

2- 230vac/50-60hz/65mA
6.5vdc/600mA
ps66/2061 IP40
IEC60950 T45/E

How can I know, how many watts each of them require?

I know that the watt = Volt x Amp. but I have problems converting the units and getting the final accurate result.

Please help.

Thank you
 
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(1 Volt)*(1 mA) = 1 mWatt
 
Consider problem 1. The appliance can be either connected to AC 230 V at 50 Hz, and 20 mA should flow. P = 230*20 mW = 4600 mW.

But if it's connected to 4 V DC, the current is 150 mA, and the power drawn is 600 mW.

How can the same appliance draw different power if it is to function properly? Unless, there is the cos phi factor in the AC, which decreases the power in AC.
 
Last edited:
Thank you gouys for your reply and help.

Shooting star, regarding your question. I don't really know. I have just copied what was written on the adapter. It's an adapter for a IP phone which is a gift from a friend in Sweden, and I live in USA, that's why am asking about the watt, becasue I wanted to use a converter to convert from the 220-240 volts of Europle to 110 volts of the states.

Thanks anyways.
 
Oh, then you just go and buy an adapter. Ask in the shop. These are very common. The only thing which is still nagging me is that the frequency in US is 60 Hz.

Also, I've never come across 4 V DC. Ask in the shop. If you buy an adapter which gives 4 V DC, that'd be the best. Look for power-in holes and see what they say.
 
Shootingstar,
I suspect that 4VDC @ 120ma is the OUTPUT rating.
 
Integral said:
Shootingstar,
I suspect that 4VDC @ 120ma is the OUTPUT rating.

That does sound most reasonable.
 

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