Wiktionary
vb. (present participle of switch on English)
Usage examples of "switching on".
He allowed Fairbank to go through first, both men switching on the flashlights.
My head began to settle and my mind started switching on the internal lights again.
She went from room to room switching on lights and calling his name, but Dundridge had vanished.
But I could also see that old light bulb switching on over their heads.
The remaining forty-two streaked upward in a ballistic path to a height of over a hundred thousand feet before tipping over at Mach-5 speed and switching on their millimeter-band Doppler homing radars.
And if you plan to use Fast User Switching on less-powerful systems with less RAM, be prepared for slowdowns.
He opened the door and paused for just a moment before switching on the lights, then led his little party to the centre of the room, where the two manuscripts awaited their inspection.