A read-only memory (ROM) is disclosed that uses the presence or absence of
linear passive electrical elements, such as resistors or capacitors, to
encode zeros and ones, permitting a large-area ROM to be fabricated,
possibly on a flexible substrate. The ROM includes a substrate, a
plurality of row conductors insulated from each other and at least
partially layered on a portion of the substrate; a plurality of column
conductors insulated from each other and from the row conductors and at
least partially layered above or below a portion of the plurality of row
conductors, a plurality of amplifiers electrically connected to the
column conductors, and at least one linear passive element attached
between the row conductors and the column conductors. An amplifier
connected to a column conductor has an input impedance much lower than
the combined parallel impedance of the linear passive elements connected
to that column, thus comprising a virtual ground, and is operable to
output a first logical state when one of the linear passive elements is
electrically connected between one of the row conductors and one of the
column conductors, and operable to output a second local state when said
one of the linear passive elements is absent between one of the row
conductors and one of the column conductors. The resistive or capacitive
arrays can be made into low-cost imagers if the resistors/capacitors are
sensitive to electromagnetic radiation or mechanical pressure.