Clock Signal: A clock signal is a periodic signal that can have different ON and OFF times. When the ON time and OFF time are equal, it is represented by a square wave. The clock signal alternates between logic high (5V) and logic low (0V) levels. It repeats with a specific time period, which is equal to twice the ON time or OFF time.
Types of Triggering
There are two types of triggering in sequential circuits: Level triggering and Edge triggering.
Level Triggering
Level triggering is based on the levels of the clock signal, either logic high or logic low. The circuit is activated only when the clock pulse is at a specific level. There are two types of level triggering:
Positive Level Triggering
In positive level triggering, the circuit is activated when the clock signal is at a logic high level.
Negative Level Triggering
In negative-level triggering, the circuit is activated when the clock signal is at a logic-low level.
Edge Triggering
Edge triggering is based on the transitions of the clock signal, either from logic low to logic high or from logic high to logic low.
Positive Edge Triggering
In positive edge triggering, the circuit is activated when there is a transition from logic low to logic high in the clock signal.
Negative Edge Triggering
In negative edge triggering, the circuit is activated when there is a transition from logic high to logic low in the clock signal.
In summary, a clock signal is a periodic signal with varying ON and OFF times. It can be represented by a square wave. Triggering in sequential circuits can be either level triggering, based on the levels of the clock signal, or edge triggering, based on the transitions of the clock signal. Positive and negative variations exist for both level triggering and edge triggering.
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