Sinewave DC to AC inverter teardown

I have earlier posted DC to AC inverter teardown that showed wat was inside one cheap “modified sinewave” inverter. Now I do a tear-down to a more expensive “true sineware” inverter PI150S from Velleman. This inverter convers 12V DC to nice sinewave 230V 50Hz AC power  (up to 150W).

View to front and back.

This unit that I have is broken (burns fuse), so let’s take a look what is inside.

There is comsiderably more electronics in this sinewave inverter than in simpler inverters I have seen.

Big transformer onupper right side is for switch mode power supply that converts 12V DC to higher voltage DC (I quess something around 300-400V or so). The switching conroler IC and transistors are next to transformer.

The ouput side that generaes the sinewave output looks quite complex. There is full control circuit board with several control ICs and quite many power transistors. On the output side after the output switching transistors there are several filtering coils and capacitors. There is for example one big coil on circuit board and common mode choke on the cable that goes to mains output connector.

What was broken? I don’t know. It burns fuse if connected to car 12V. If connected to lab power supply (that can outpuyt many amperes), pulls so much current that voltage drops to few volts.

I did not consider this worth to repair. I used his earlier to power a laptop in the car. I replaced this inverter + original mains power supply approach with universal 12V laptop power supply (more convient and smaller).



  1. Scamfighter says:

    Can you advise a good inverter for a car? I’m very afraid to buy a poor-quality product.

    • Tomi Engdahl says:

      Hard to recommend anything currently on the market.
      The inverters I have bought have been bought many years ago.
      This specific inverter I showed here is quite expensive (around 100 Euros) and it still failed after few years at car.


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