Binary coded decimal resistive load and network

1. An apparatus configured to provide a variable resistance, comprising:

a plurality of resistive elements, each resistive element having a respective resistance; and

a plurality of switches, each of the switches coupled to a respective one of the plurality of resistive elements, each of the switches configured to selectively include the respective one of the resistive elements in said variable resistance;

wherein the resistive elements and the switches are arranged in a binary-coded decimal scheme, wherein the plurality of resistors are arranged in a plurality of resistor groups, wherein each resistor group comprises four resistors having respective resistances of about 1×10 X , about 2×10 X , about 4×10 X , and about 8×10 X , where X is an integer.

2. The apparatus of claim 1 , wherein each resistor within a single resistor group has a respective resistance on the same order as each other resistor within the single resistor group.

3. The apparatus of claim 1 , wherein each resistor group has a respective value of X, wherein the respective resistance of each resistor in a group is determined according to the group's respective value of X.

4. The apparatus of claim 1 , wherein a variable combined resistance of one of the resistor groups is about 1×10 N ohms to about 15×10 N ohms, where N is an integer.

5. The apparatus of claim 4 , wherein each resistor group has a different value of N according to which the variable combined resistance of the resistor group is determined.

6. The apparatus of claim 1 , wherein the apparatus is configured for automatic and manual use.

7. The apparatus of claim 1 , wherein an open switch includes a respective resistive element in said variable resistance.

8. The apparatus of claim 1 , wherein said variable resistance is bidirectional.

9. A method comprising:

providing an apparatus comprising:

a plurality of resistive elements, each resistive element having a respective resistance; and

a plurality of switches, each of the switches coupled to a respective one of the plurality of resistive elements, each of the switches configured selectively include the respective one of the resistive elements in the variable resistance;

wherein the resistive elements and the switches are arranged in a binary-coded decimal scheme, wherein the plurality of resistors are arranged in a plurality of resistor groups, wherein each resistor group comprises four resistors having respective resistances of about 1×10 X , about 2×10 X , about 4×10 X , and about 8×10 X , where X is an integer; and

automatically actuating the switches to provide a predetermined sequence of resistances.

10. The method of claim 9 , wherein the automatically actuating step comprises actuating different ones of the plurality of switches to provide a sequence of ascending and/or descending resistances for said power supply.

11. The method of claim 9 , wherein an open switch corresponds to the respective resistive element contributing to the variable resistance.

12. The method of claim 9 , wherein the automatically actuating step comprises opening at least one of the plurality of switches to decrement the variable resistance.

13. The method of claim 9 , where in the automatically actuating step is performed according to instructions contained in computer software.

14. The method of claim 13 , wherein a maximum value of the variable resistance is provided when all of the switches are open.

15. An apparatus configured to provide a variable resistance, comprising:

a plurality of switched resistive elements, each resistive element having a respective resistance, the resistive elements grouped to provide a variable resistance according to a binary-coded decimal value, wherein the plurality of resistors are arranged in a plurality of resistor groups, wherein each resistor group comprises four resistors having respective resistances of about 1×10 X , about 2×10 X , about 4×10 X , and about 8×10 X , where X is an integer;

wherein the resistive elements are configured for automatic switching to selectively contribute to the variable resistance.

16. The apparatus of claim 15 , further comprising a plurality of switches, wherein each of the plurality of switches is coupled to a respective one of the plurality of resistive elements.

17. The apparatus of claim 16 , wherein a maximum value of the variable resistance corresponds to all of the switches being open.

18. The apparatus of claim 16 , wherein a minimum value of the variable resistance corresponds to all of the switches being closed.