The CD4093B consists of four Schmitt-trigger circuits. Each circuit functions as a 2-input NAND gate with Schmitt-trigger action on both inputs. The gate switches at different points for positive and negative-going signals. The difference between the positive (VTa) and the negative voltage (VTb) isdefined as hysteresis voltage (VH). All outputs have equal source and sink currents and conform to standard B-series output drive.