To　overcome　the　disadvantages　of　chronoamperometry　we　report　a　novel　electrochemical　method　where　a　peak　current　is　quickly　generated　for　the　current　vs　time　curve　by　changing　the　waveform　of　voltage　excitation　in　the　working　electrode.　In　particular,　we　derived　a　mathematical　model　to　illustrate　the　principle　of　this　method　and　it　can　also　be　used　to　demonstrate　that　the　peak　current　is　linear　with　regards　to　the　concentration　of　the　target　substance.　Moreover,　we　developed　a　device　with　an　improved　electrochemical　circuit　using　a　control　element　from　control　theory　to　change　the　waveform　of　voltage　excitation.　The　improved　circuit　can　detect　the　peak　automatically　without　a　precise　sample　time.　Finally,　the　device　was　used　to　study　the　electrochemical　behavior　of　K-3[Fe(CN)(6)]　and　3,3＇,5,5＇-tetramethylbenzidine　(TMB).　We　show　that　the　method　has　a　better　signal　to　noise　ratio　and　higher　sensitivity　than　chronoamperometry.　The　obtained　peak　current　is　linear　with　regards　to　the　concentration　of　the　target　substance　and　can　be　quickly　detected　without　a　precise　sample　time.