What is Schmitt Trigger?
The Schmitt Trigger was designed by American researcher Otto H Schmitt in 1934. A Schmitt trigger is a type of comparator with hysteresis. It takes an analog signal as an input and converts it into a perfect and stable output signal. It does this by applying positive feedback to the non-inverting input of a comparator. The main purpose of the Schmitt trigger is to eliminate noise or jitter in the input signal and produce a stable output. This is especially true when dealing with signals that switch between two voltage levels.
Characteristics of the Schmitt Trigger
- Hysteresis: It is the defining feature of the Schmitt Trigger. It means that the output voltage depends on the previous values of input signals. This hysteresis helps in creating two different voltage thresholds. The first threshold value is for the rising input and the other is for the falling input signal.
a fundamental - Noise Rejection: The hysteresis helps in noise rejection. When there are small fluctuations in the input signal, the output signal does not change or does not show false values. It helps in preventing the noise coming from the noisy environment.
- Bistable Operation: Bistable operation means that it has two possible stable states i.e., ‘high state’ and ‘low state’. When the upper threshold value is crossed by the input signal, the output signal changes its state to ‘high’. The output signal remains in this state until the input signal value falls below the threshold value. When the value falls below the threshold value, the state changes to ‘low’.
Schmitt Trigger
We use Schmitt Triggers in digital electronics. It is used for rejecting the noise from the input signals by using the hysteresis curve. To provide accurate and more stable results, it uses two threshold voltages i.e., upper threshold voltage (VUT) and lower threshold voltage (VLT). It is mainly used in signal conditioning applications to remove noise from signals which is used in digital circuits, particularly mechanical contact bounce in switches. In this article, we will learn more about Schmitt Trigger, its working, and its applications.
Table of Content
- What is Schmitt Trigger?
- Working
- Transfer Characteristics
- Types
- Uses
- Schmitt Trigger Vs Comparator
- Advantages and Disadvantages
- Applications