 Clock pulse triggering of flip-flops. Gates are the building block of logic circuits. Their primary function is to perform decision-making operations. Flip-flops are the building block of digital circuits. Their primary function is to store binary bits. Some types of flip-flops only allow data to be applied to their inputs when a pulse is applied to its clock terminal. When flip-flops using clock terminals are connected in groups, they operate as sequential circuits in the form of counters or registers which store multi-bit numbers and words called data. Sequential circuits are dependent on clock pulses applied to their inputs. For example, the number in a counter is determined by the number of clock pulses applied. With a register, multi-bit data is shifted one position each time a clock pulse is applied. The result of flip-flops responding to a clock input is called clock pulse triggering, of which there are four types. Each type responds to a clock pulse in one of four ways. High-level triggering, low-level triggering, positive edge triggering, and negative edge triggering. High-level triggering, one type of flip-flop responds to a clock signal during the time at which it is in the logic high state. This type is identified by a straight lead at the clock input as shown below. Low-level triggering, another type of flip-flop responds to a clock signal during the time at which it is in the logic low state. This type is identified by a clock input lead with a low state indicator bubble as shown below. Negative edge triggering, a third type of flip-flop responds to a clock signal during the low to high transition of a clock pulse. This type is identified by a clock input lead with a triangle as shown below. Negative edge triggering, the fourth type of flip-flop responds to a clock signal during the high to low transition of a clock pulse. This type is identified by a clock input lead with a low state indicator and triangle as shown below. You have completed this activity on the clock pulse triggering of flip-flops.