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) is defined as hysteresis voltage (VH). All outputs have equal source and sink currents and conform to standard B-series output drive (see Static Electrical Characteristics).