Byanalyzingthethreshold-jumpingofSchmittcircuits,thispaperindicatesthatthecoreelementrealizingthisfunctioninbinaryTTLSchmittcircuitsisthedifferentialcurrentswitchwithcontrollablethreshold.Basedonthecharacteristichavingtwokindsofsignal-detectionthresholdinternaryTTLcircuits,aternaryTTLSchmittcircuithavingtwicereactionsofthreshold-jumpingisdesigned.ThesimulationwithPSPICEprovesthatthedesignedcircuithasidealfunctionofSchmittcircuits.