ENGINEERING LOGIC DIAGRAMSDOE-HDBK-1016/2-93Logic DiagramsPR-05Page 10Rev. 0Engineering Logic Diagrams SummaryThis chapter reviewed the seven basic symbols used on logic diagrams and thesymbols used for six of the more complex logic devices.There are three types of time delay devices:Type One - delays the output signal for a specified period of timeType Two - only generates an output for the specified period of timeType Three - receipt of an input signal triggers the device to output asignal for the specified time, regardless of the duration of the inputThis device, although occasionally used on component and system type logic diagrams,is principally used in solid state logic diagrams (computers).Binary counter - Several types of binary counters exist, all of which are constructed offlip-flops. The purpose of a counter is to allow a computer to count higher than 1,which is the highest number a single flip-flop can represent. By ganging flip-flops,higher binary numbers can be constructed. Figure 10 illustrates a common symbol usedfor a binary counter.Shift register - Is a storage device constructed of flip-flops that is used in computers toprovide temporary storage of a binary word. Figure 10 shows the common symbol usedfor a shift register.Half adder - Is a logic circuit that is used in computer circuits to allow the computer to"carry" numbers when it is performing mathematical operations (for example to performthe addition of 9 + 2, a single 10s unit must be "carried" from the ones column to thetens column). Figure 10 illustrates the symbol used for a half adder.SummaryThe important information in this chapter is summarized below.

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