二、Below is a series of oscillograms showing the drain voltage (VDS) and current (ID) of U1, measured with the different diodes listed in question 1*. Can you match the resultant waveforms to the diode(s) that generated them?
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Selecting diodes with different recovery times for the clamp diode D1 has an interesting effect. The table shows the measured input power and resultant efficiency for the different diode tested. Can you explain the changes in efficiency and why the rectifier diode must be glass-passivated?
Diode PIN (W) POUT (W) η (%)
UF4005 36.18 30.23 83.6
1N4937 36.07 30.23 83.8
1N4007GP* 35.92 30.23 84.2
*Glass Passivated