How To Turn On/Off Monitor with Delphi

In case that you need to shutdown the monitor to conserver power during program execution, you can simple turn your monitor off by calling below function.

uses windows;

SendMessage(Application.Handle, WM_SYSCOMMAND, SC_MONITORPOWER, 2);

If you need to turn your monitor on, you can do it by calling below function.

uses windows;

SendMessage(Application.Handle, WM_SYSCOMMAND, SC_MONITORPOWER, $FFFFFFFF);

Final tip to let you know is making your monitor to stand by mode which consumes less power.

uses windows;

SendMessage(Application.Handle, WM_SYSCOMMAND, SC_MONITORPOWER, 1);