Response to the following questions:
1. A designer of an instrument that must operate over a wide supply-voltage range, noting that a diode's junction-voltage drop is relatively independent of junction current, considers the use of a large diode to establish a small relatively constant voltage. A power diode, for which the nominal current at 0.8 V is 10 A, is available. If the current source feeding the diode changes in the range 1 mA to 3 mA and if, in addition, the temperature changes by ±20°C, what is the expected range of diode voltage?
2. As an alternative to the idea suggested in Problem v4.32, the designer considers a second approach to producing a relatively constant small voltage from a variable current supply: It relies on the ability to make quite accurate copies of any small current that is available (using a process called current mirroring). The designer proposes to use this idea to supply two diodes of different junction areas with equal currents and to measure their junction-voltage difference.
Two types of diodes are available: for a forward voltage of 700 mV, one conducts 0.1 mA, while the other conducts 1 A. Now, for identical currents in the range of 1 mA to 3 mA supplied to each, what range of difference voltages result? What is the effect of a temperature change of±20°Con this arrangement?