Javalab
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Lars Drud Nielsen ldn@oersted.dtu.dk |
Observe that, for given settings of the three vertical components in the diagram, the optimal power transfer ratio from the source (> VZ) to the load is obtained by adjusting the resistance of the horizontal series resistor exactly to hit the breakdown point of the Zener diode. Larger series resistance values will result in a resistive voltage divider (IZ = 0) with a decreasing voltage fraction across the load. Smaller series resistance values will leave the load current unchanged but will increase the total current (IZ > 0).
Exercise: A voltage source is available with an output voltage that may fluctuate between 6 V and 8 V. Design a voltage regulator to supply a constant voltage of 5 V (= VZ) to a load that may vary from 8 kW to 12 kW. (Determine a fixed series resistance value with minimal over-all power losses in mind!)