Lenovo A7-40 Tablet - Manual (Page 3)

Tip:The Lenovo TAB A7 models & versions are as below:
1-2 Buttons
On/Off Button
To turn on your tablet, press and hold this button for about 3 seconds,
then release it.
If your tablet is turned on, press this button to deactivate the display. If
the display is deactivated, press this button to activate the display.
To turn off your tablet, press and hold this button for about 1 second,
then select OK in the Power off pop-up window to shut down your
tablet.
NOTE: When connecting to a computer with a USB cable, make sure that the
battery power is sufficient for normal operation; otherwise, charge with the AC
power adapter before USB connection.