This part is a kind of semiconductor called 74LS12.

Function of this product has Dual Retriggerable One-Shot with Clear and Complementary Outputs.

Manufacturers : Fairchild Semiconductor

Image and pinout :

Some of the text within the PDF file :

w w w . D a t a S h e e t 4 U . c o m DM74LS123 Dual Retriggerable One-Shot with Clear and Complementary Outputs August 1986 Revised April 2000 DM74LS123 Dual Retriggerable One-Shot with Clear and Complementary Outputs General Description The DM74LS123 is a dual retriggerable monostable multivibrator capable of generating output pulses from a few nano-seconds to extremely long duration up to 100% duty cycle. Each device has three inputs permitting the choice of either leading edge or trailing edge triggering. Pin (A) is an active-LOW transition trigger input and pin (B) is an activeHIGH transition trigger input. The clear (CLR) input terminates the output pulse at a predetermined time independent of the timing components. The clear input also serves as a trigger input when it is pulsed [ ... ]

74LS12 PDF Datasheet Download