Registers, formed from collection of flip -flops, are used to store or manipulate data or both. Input and output function associated with registers include Parallel input/ Parallel output Serial input/ Serial output Parallel input/ Serial output OSerial input parallel output
simple counters Counting is a fundamental function of digital circuits. A digital counter consists of a collection of flip-flops that change states (set or reset) in a prescribed sequence
FLIP-FLOPS Flip-flops are digital devices that have the ability to store binary information after the excitation input has changed. They are considered to be the basic memory cell for the majority of electronic binary data storage applications. This section explores the flip-flop from a functional perspective
Fluorine and its Compounds 一、氟的电负性(electronegativity)为4.0,是电负性最大的元素。氟的化合物存在于人体 中:主要存在于牙和骨头中,在自然界中以萤石(Fluorspar):CaF2、冰晶石(cryolite): na3aif6和氟磷灰石(fluorapatite):Cas(PO4)3F的矿物存在