GB1349376A - Read-only memory device - Google Patents

Abstract

1349376 Read only memory; code converter AGES SpA AZIENDA GENERALE ELETTRONICA SERVOMECCANISMI 5 May 1971 [6 May 1970] 13147/71 Headings G4A and G4H A capacitive read only memory is provided, e.g. for code conversion. A first printed circuit board comprises 16 electrically conductive strips 3, any one of which may be selected using one transistor 1 and one transistor 2 and positively charged by cutting off transistor T1 after transistor T2. A second printed circuit 6 is placed above the first circuit, the two being separated by a thin electrically insulating layer, the circuit 6 having electrically conducting areas 7, 8, 9. The areas 7 form capacitances with the charged strips 3 and four output pulses pass to output amplifiers 12. Where there is no area 7 only a small output is received which is distinguishable from the said pulses. Mechanical presses keep the circuits mutually aligned and screens protect the memory from outside interference. A fresh read only memory can be made by inserting a fresh circuit 6. A modification (Fig. 2, not shown) provides two complementary outputs on each row, and 12 is then constituted by a differential amplifier.