Hysteresis voltage comparator, also known as Schmidt trigger, has two stable states. Different from general flip-flops, Schmitt flip-flops are triggered by potential, and their state is maintained by the potential of the input signal. Schmidt trigger has different threshold voltages for negative falling and positive rising input signals.
Standard Schmitt trigger, when the input voltage is higher than the forward threshold voltage, the output is high; When the input voltage is lower than the negative threshold voltage, the output is low; When the input is between positive and negative threshold voltages, the output is unchanged, that is, when the output changes from high level to low level or from low level to high level, the corresponding threshold voltages are different.
Extended data
Application of hysteresis voltage comparator circuit;
1, waveform conversion
Triangular wave, sine wave, periodic wave, etc. Can be turned into a rectangular wave.
2. Pulse wave shaping
In digital system, rectangular pulse often appears waveform distortion during transmission, and the rising edge and falling edge are not ideal. After shaping by Schmidt trigger, an ideal rectangular pulse can be obtained.
3. Pulse amplitude identification
When pulse signals with different and irregular amplitudes are applied to the input end of Schmidt trigger, pulse signals with amplitudes greater than the preset values can be selected for output.
4. Form a multivibrator.
Signals with different amplitudes will generate rectangular pulses and rectangular wave pulse signals after passing through Schmidt trigger with appropriate capacitance, which are often used as pulse signal sources and clock signals in sequential circuits.
A concise course of analog electronic technology (second edition) Yang Suxing? Editor in chief? Higher Education Press? Chapter VII Signal Processing Circuit? 7.2? Voltage comparator
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