A practical guide covering op‑amp oscillator circuits, bandwidth estimation, voltage conversion, low‑signal amplification and other design topics.
This guide, published by the Electronic Engineering Series, provides a collection of classic Q&A and technical trends for operational amplifier design. It covers a wide range of topics such as sine‑wave oscillator circuits, multi‑stage amplifier bandwidth estimation, converting negative voltages to positive, extracting and amplifying weak AC signals, and single‑supply op‑amp applications.
Each section includes practical circuit examples, component recommendations (e.g., LM358, LMH6738, AD620) and design tips like proper biasing, feedback network selection, and noise reduction. The material is aimed at engineers who need hands‑on solutions for precision analog design. This manual is written in Chinese.
| LM358 supply range | +/- 2.75 V (max) |
|---|---|
| 2N7000 MOSFET rating | 60 V, 7.5 Ω |
| 1N4148 diode used | Standard switching diode |
Use high‑quality capacitors, add power‑supply decoupling, and filter the oscillator output. A bridge‑type oscillator with AGC and diode limiting can also reduce distortion.
Multiply the gain of each stage by its –3 dB bandwidth (gain‑bandwidth product) and ensure the overall bandwidth meets the design requirement.
The SGM358 can work with a ±2.75 V supply (max), and the LM358 can be used with ±5 V if the circuit is designed accordingly.
The reverse recovery time of the diodes (D1 and D2) keeps them conducting briefly after the input changes polarity, pulling the output toward the supply rail.