Method and apparatus for analog testing

Abstract

A sense circuit for detecting charge on a TFT/LCD cell capacitor, which comprises a first, integrating circuit attached to the TFT/LCD cell capacitor through a data line, wherein the data line is connected to the cell capacitance through a thin film transistor. The thin film transistor including a gate, a drain and a source, wherein the source is connected to the cell capacitor and the drain is connected to the data line. A first, gate supply voltage adapted to drive the gate of the thin film transistor. And a reset circuit adapted to reset the integrating circuit. This embodiment may further include a source for charging said cell capacitor prior to measuring the charge. Further, a method of testing a partially constructed electronic circuit, for example the cell of an LCD, prior to installation of the backplate. The partial circuit comprising an array of contact electrodes, for example cell pad electrodes and an array of address electrodes, for example gate electrodes. The address electrodes being electrically connected to the contact electrodes. The method comprising the steps of providing the partial circuit with a test electrode, for example an adjacent data electrode extending alongside but spaced from at least a first contact electrode; and measuring the capacitance between the first contact electrode and the test electrode.