Triggering is the process of making a circuit active. Triggering allows the circuit to take input and generate output. The circuit will become active at certain states of clock pulse depending upon the triggering methods we used.
What is a Clock?
A clock is a signal that oscillates between a high and a low state. It is used to coordinate the actions of a digital circuit (like a metronome).
The transition of a signal from LOW to HIGH or from HIGH to LOW is called an edge. A LOW to HIGH transition is a rising edge and a HIGH to LOW transition is a falling edge.
Types of Triggering
There are two types of triggering
- Edge triggering
- Level triggering
Level triggering
A level-triggered circuit will become active when the clock pulse is at a certain level. Based on which level (HIGH / LOW ) the circuit is activated level triggering is again classified as negative level triggering circuits and positive level triggering. In negative edge triggering the circuit become active when the clock pulse is low. Similarly in positive edge triggering the circuit become active when the clock pulse is high.
Edge triggering
An edge-triggered circuit will become active at a positive or negative edge of the clock signal. When a clock signal goes from low to high, it is called a rising edge (positive edge). A positive edge-triggered circuit will take input on the rising edge of the clock signal. Similarly, when a clock signal goes from high to low, it is called a falling edge (negative edge). A negative edge-triggered circuit will take input on the falling edge of the clock signal.