Microchips are K155AG3 dual monostable multivibrator with restarting. They contain 156 integral elements. K155AG3: Supply voltage .......... 4.75 - 5.25 V Low-level input voltage .......... <0.4 V High-level input voltage ..........> 2.4 V Low level input current .......... <16 mA High-level output current .......... <0.8 mA Loading capacity .......... <15 pF The duration of the front and cutoff of the input pulse is <150 ns