70W consumption with 5V 8A AC/DC Power Adapter

[JavaLaurence]

Hi,

 

I've got the following hooked up to a Watt meter: a Tinkerforge 8A AC/DC Power Adapter, a Tinkerforge 50-LED strip, a Brick and LED Strip, and a Raspberry Pi B to run my logic.

 

The Watt meter indicates a 69-70W consumption (I'm animating the LEDs somewhat, so their brightness varies).

 

Even when all LEDs are dark, I'm getting 67-68W.

 

What is consuming this? Neither the Tinkerforge nor Raspberry consume more than a few Watts... and dark LEDs ..?

 

Does the power adapter itself consume anything?

 

Thx for any insights.

 

[borg]

The 5V 8A AC/DC Power Adapter is a switched-mode power supply. I would guess that your watt meter is not able to measure switching power supplies correctly.

 

Waveforms for switched-mode power supplies as used for much electronic equipment may be very far from sinusoidal' date=' leading to unknown and possibly large errors at any power. This may not be specified in the meter's manual.[/quote']

[JavaLaurence]

Thanks.. that would explain a lot.