  Calorimeters with silicon detectors have many unique features and are
proposed for several world-leading experiments. We discuss the tests of the
first three 18x18 cm$^2$ layers segmented into 1024 pixels of the technological
prototype of the silicon-tungsten electromagnetic calorimeter for a future
$e^+e^-$ collider. The tests have beem performed in November 2015 at CERN SPS
beam line.
