Combined　modulus　and　impedance　spectra　are　widely　employed　to　explore　electrical　inhomogeneity　and　carriers＇　behaviors　in　dielectric　ceramics　based　on　equivalent　circuit.　However,　discrepancies　are　found　between　practical　dielectric　responses　and　widely　proposed　equivalent　circuits.　Taking　ZnO　varistor　ceramics　as　an　example,　a　low-frequency　dielectric　relaxation,　which　can　be　detected　in　practical　dielectric　spectroscopy,　is　overlooked　in　simulated　dielectric　spectroscopy　based　on　the　proposed　equivalent　circuit　according　to　modulus　and　impedance　spectra.　Therefore,　equivalent　circuits　are　frequently　incomplete　because　the　real　low-frequency　dielectric　response　is　unable　to　be　characterized　from　them.　The　problem　originates　from　debatable　understanding　of　frequency　responses　in　modulus　and　impedance　spectra.　The　low-frequency　peak　in　modulus　spectroscopy　is　proved　originating　from　DC　conductance　instead　of　a　real　dielectric　relaxation　and　the　involvement　of　DC　conductance　component　makes　a　low-frequency　dielectric　relaxation　unable　to　be　characterized　in　modulus　spectroscopy.　Therefore,　improved　dielectric　spectroscopy　eliminating　the　component　of　DC　conductance　is　proposed　and　a　clear　peak　corresponding　to　the　low-frequency　dielectric　relaxation　appears.　In　addition,　a　modified　equivalent　circuit　which　is　in　accordance　with　practical　dielectric　responses　in　not　only　modulus　and　impedance　spectra　but　also　dielectric　spectroscopy　is　presented.