The DM74LS122 is a retriggerable monostable multivibrator featuring both positive and negative edge triggering with complementary outputs An internal 10 kX timing resistor is provided for design convenience minimizing component count and layout problems This device can be used with a single external capacitor The 'LS122 has two active-low transition triggering inputs (A) two active-high transition triggering inputs (B) and a CLEAR input that terminates the output pulse width at a predetermined time independent of the timing components The clear (CLR) input also serves as a trigger input when it is pulsed with a low level pulse transition (