双向限幅电路模型

落日映苍穹つ 2022-11-13 05:20 127阅读 0赞

\[分析步骤\]

将两个二极管D1、D2全部开路.

由KVL方程, 可知 ui+V2+VD2-VR1=0, ui-V1-VD1-VR1=0.

将V1=V2=12V代入上式, 可知 ui+12+VD2-VR1=0, ui-12-VD1-VR1=0.

由于两个二极管全部开路, 那么电路中无电流, 也就意味着VR1=0V. 将此条件代入上式, 得 ui+12+VD2=0, ui-12-VD1=0.

这里使用二极管的折线模型作为近似分析的工具. 当VD1≥0.7V时, D1导通, ui=VD1+12≥12.7V, 此时uo=12.7V; 当VD2≥0.7V时, D2导通, ui=-VD2-12≤-12.7V, 此时uo=-12.7V. ui＜12.7V时, D1截止, ui>-12.7V时, D2截止—— -12.7V＜ui＜12,7V时, D1和D2都截止, 此时uo=ui.

综上所述, uo=ui, -12.7V＜ui＜12.7V; uo=-12.7V, ui≤-12.7V; uo=12.7V, ui≥12.7V.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70][]

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\[注\]示波器屏幕中的一格(横向)为0.5ms.

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