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5volt writes –

Are electronic devices really in a very low power mode when on stand-by? Also, how much energy am I wasting for powering devices when not in use?

I wanted to check it out and decided to build a device capable to detect stand-by mode of my electronic devices and start metering energy used. All this had to be done automatically without my intervention. Metering would start upon entering stand-by and stopped upon exiting.
To do so I needed an energy meter and a current gauge to monitor the current of mains supplied devices and start/stop metering.
For the meter I first looked for silicon, of course. Energy metering is a hot issue with a lot of chip makers and many of them supply cheap solutions.

The project was proceeding when recently I was lucky enough to find two electromechanical meters at a local special trash collecting center (electrical, white goods, furniture).

Actually there should be a plenty of these scrap meters available here as the local electric company is replacing these meters with remotely controlled electronic meters.

I took them along with two VCRs and a printer. The first meter I opened and dismantled to satisfy my inner primary need. The second meter I decided to use in place of the silicon-based one; also, the ready made electromechanical meter solved the calibration issue.

How green is my green electronics – Link.


  • mikiex

    I’m wondering if you or someone else knows
    How much power it takes to charge 4 AA batteries
    by mains power, including losses.