Bistable Multivibrators (aka Schmitt Triggers) (3): Non-inverting

Bistable Multivibrators (aka Schmitt Triggers) (3): Non-inverting

by Vincent Chang

Formal & Physical Sciences Engineering & Technology TJFElectronics engineeringTJFCElectronics: circuits and components
🎙 Vincent Chang 👥 2K 📅 October 31, 2021 ⏱ 16 min 👁 70 📄 tutorial 🧭 2026-08-17
Available in: English (current) Français

Keywords

non-inverting Schmitt triggerthreshold voltagepositive feedbackhysteresisop-amp

Summary

This educational video, part of a series on bistable multivibrators, focuses on the non-inverting configuration, also known as a non-inverting Schmitt trigger. The instructor, Vincent Chang, begins by contrasting this circuit with the previously covered inverting version, highlighting that the input signal is applied to the non-inverting terminal of the op-amp. He explains that due to positive feedback, the circuit has two stable states (red and blue), corresponding to the output saturation voltages. The core of the lesson is the derivation of the two threshold voltages (Vt+ and Vt-) using the principle of superposition to express V+ as a function of Vi and Vo. By setting V+ = 0 and substituting the respective output states, he obtains Vt- = -VM * R1 / (2R2) and Vt+ = +VM * R1 / (2R2). The instructor emphasizes the importance of the hysteresis window and the direction of traversal (counterclockwise for non-inverting) compared to the inverting configuration. He uses a physical analogy of a ball on a hill to illustrate the switching behavior. The video concludes with a summary contrasting the two configurations and a preview of the next topic: astable multivibrators and square wave generators.

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Critical Evaluation

Value of the Information & Strength of the Argument

The video provides a solid, rigorous explanation of the non-inverting Schmitt trigger, deriving the threshold voltages from first principles. The argumentation is logical and well-structured, with the instructor carefully guiding the viewer through each step. The use of superposition is clearly explained, and the physical analogy helps intuitive understanding. The comparison with the inverting configuration reinforces the concepts and highlights the key differences. The content is valuable for students and engineers seeking a deeper understanding of comparator circuits and hysteresis.

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Title / Content Match

The title accurately reflects the content, which focuses on the non-inverting configuration of bistable multivibrators (Schmitt triggers).

Quality & Reliability

8/10

The content is a clear, step-by-step tutorial on non-inverting bistable multivibrators, based on fundamental circuit theory. The instructor demonstrates a thorough understanding of the subject, explaining the derivation of threshold voltages and the hysteresis behavior. The presentation is logical and pedagogically sound, though it lacks formal citations or references to external sources.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Contribution & Novelties

This video provides a clear and detailed tutorial on the non-inverting Schmitt trigger, a fundamental building block in analog electronics. It offers a step-by-step derivation of the threshold voltages and explains the hysteresis behavior, which is essential for understanding comparator circuits. The comparison with the inverting configuration helps solidify the concepts.

Pour aller plus loin :

  • Schmitt trigger - Wikipedia — Provides a general overview of Schmitt triggers, including applications and history.
  • Op-amp comparator circuits - Electronics Tutorials — Covers comparator circuits and hysteresis in more detail.
  • Bistable Multivibrator - Wikipedia — Explains the different types of multivibrators, including bistable, and their uses.

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Radar Profile

The radar profile shows high scores in quality of information and reliability, with moderate scores in quantity and technical level. This indicates a focused, well-explained tutorial that may not cover a broad range of topics but provides deep insight into the specific subject.

Reliability 8/10