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stn0091
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Homework Statement
Plot the waveforms for capacitor voltage VC, output voltage Vo, and diode voltage Vd given that Vs is a 20 Vpp triangle wave with period T. Use CVD model with diode VON = 0.7 V.
Homework Equations
KVLs?
The Attempt at a Solution
From my basic understanding of a clamper, I can see that the output is offset by +2 V. Thus Vo begins at +2v, Vc begins at -2V, and the diode voltage begins at 0V and heads towards -10V (off, reverse bias).
However, I can't manage to show this analytically.
KVL around the left side gives:
Vs - Vc + Vd - 2V = 0
At the same time, I know that Vo + Vd - 2 = 0.
I can't really solve anything with just these two equations though.
I can say that Vs - Vc = Vo, but these equations just take me in circles.
Again, I understand that Vo starts at 2V and rises in step with Vs. With that said, Vo = 12 V at when Vs reaches its first 10V peak. At T/2 when the input becomes negative, the diode turns on and the capacitor can start charging. With the diode on, output Vo is clamped to 2V - 0.7V = 1.3V. The 0.7V is the diode drop from the CVD model.
It stays on until 3T/4. By that point, the capacitor has charged to -11.3V. From 3T/4 onwards, diode remains off. Capacitor has no discharge path and remains at -11.3V. At the second 10V peak, Vo is 21.3V.
I just don't know how to show ANY of that with work, which doesn't earn me any points when I have to analyze this on a test.
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