Search results
Results from the WOW.Com Content Network
There are two sets of symbols for elementary logic gates in common use, both defined in ANSI/IEEE Std 91-1984 and its supplement ANSI/IEEE Std 91a-1991. The "distinctive shape" set, based on traditional schematics, is used for simple drawings and derives from United States Military Standard MIL-STD-806 of the 1950s and 1960s. [ 19 ]
There is also IEC 61131-3 – for ladder-logic symbols. JIC JIC (Joint Industrial Council) symbols as approved and adopted by the NMTBA (National Machine Tool Builders Association). They have been extracted from the Appendix of the NMTBA Specification EGPl-1967. ANSI Y32.2-1975 (also known as IEEE Std 315-1975 [1] or CSA Z99-1975).
In logic, a set of symbols is commonly used to express logical representation. The following table lists many common symbols, together with their name, how they should be read out loud, and the related field of mathematics.
IMPLY can be denoted in algebraic expressions with the logic symbol right-facing arrow (→). Logically, it is equivalent to material implication, and the logical expression ¬A v B. There are two symbols for IMPLY gates: the traditional symbol and the IEEE symbol. For more information see Logic gate symbols.
There are two logic gate symbols currently representing the OR gate: the American (ANSI or 'military') symbol and the IEC ('European' or 'rectangular') symbol. The DIN symbol is deprecated. [5] [6] The "≥1" on the IEC symbol indicates that the output is activated by at least one active input. [7]
The AND gate is a basic digital logic gate that implements the logical conjunction (∧) from mathematical logic – AND gates behave according to there truth table. A HIGH output (1) results only if all the inputs to the AND gate are HIGH (1). If all of the inputs to the AND gate are not HIGH, a LOW (0) is outputted.
Diagram of the NAND gates in a CMOS type 4011 integrated circuit. NAND gates are basic logic gates, and as such they are recognised in TTL and CMOS ICs. The standard, 4000 series, CMOS IC is the 4011, which includes four independent, two-input, NAND gates. These devices are available from many semiconductor manufacturers.
Most integrated circuits manufactured recently are built using CMOS, using 2 transistors for a NOT gate, 6 transistors for a 3-in NAND gate, etc. Counting transistors is a more objective method of measuring the size of an integrated circuit than counting logic gates, because many integrated circuits include a bunch of transistors outside of any ...