Tachistoscope Fall Door Type with card and Manual

Tachistoscope falling door type is one which usually has a fixed
exposure time. This consists of a Wooden Screen with a window
in the middle which is covered by a movable falling shutter.This
falling shutter can be closed or opened with the help of a lever at
the top on the back side of the screen.The exposure time is
th usually 1/10 of a second.