BISTABLE ELECTRICAL DATA STORAGE CIRCUIT

• Main Author: SIEGFRIED KURT WIEDMANN
• Format: Patent
• Language: English
• Published: 13.01.1971
• Subjects: BASIC ELECTRIC ELEMENTS; BASIC ELECTRONIC CIRCUITRY; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; INFORMATION STORAGE; PHYSICS; PULSE TECHNIQUE; SEMICONDUCTOR DEVICES; STATIC STORES

1,218,896. Transistor bi-stable circuits. INTERNATIONAL BUSINESS MACHINES CORP. 30 April, 1969 [2 May, 1968], No. 21912/69. Heading H3T. [Also in Division H1] A bi-stable circuit such as a cross-coupled pair of transistors T1, T2 has a read/write circuit, comprising for example transistors T3, T4 receiving an address pulse at their commoned bases, reaction being effected by feeding extra current to the bi-stable, and writing by extracting current from the bi-stable. Thus, if T2 is ON, an address pulse (positive) at A causes transistor T4 to conduct and feed current into T2, its collector B1 potential consequently falling and turning OFF a transistor T8 of an emitter-coupled pair T7, T8 to give a positive output pulse. When writing, one transistor, say T6, of a write input pair T5, T6 is turned ON by a positive pulse at its base, thus causing the potential at T4 collector B1, to which T6 collector is coupled, to fall. If T2 is OFF, the emitter of T4 will be positive and this transistor will operate in reverse when a positive address pulse occurs at A. The current thus extracted at the junction 15 of collector resistors R21, R22 causes the point 15 and T2 collector C2 to fall to a certain extent, turning T1 OFF. The reciprocal coupling completes the changeover, and T2 comes ON. An integrated circuit form of construction is disclosed (Figs. 2, 3, not shown).