Digital multi-meter

• US 10,126,331 B2
• Filed: 12/29/2016
• Issued: 11/13/2018
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Original Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Inventors: Cabot, Benjamin Oliver Ryan, Nguyen, Evans H.
• Primary Examiner(s): Patel, Paresh H
• Application Number:
  US15/393,512
• Publication Number:
  US 20170108537A1
• Time in Patent Office: 684 Days
• Field of Search: None
• CPC Class Codes: G01R 15/09 Autoranging circuits
• CPC Class Codes: G01R 15/125 for digital multimeters

Abstract

A multi-meter including a current input, a common input, a display, a first current measurement circuit, a second current measurement circuit, and a controller. The controller includes a first input and a second input. The controller operable to receive a first voltage from the first current measurement circuit at the first input, receive a second voltage from the second current measurement circuit at the second input, determine a value for a current being measured based on the first voltage if the first voltage is below a predetermined threshold, determine a value for a current being measured based on the second voltage if the first voltage is above the predetermined threshold, generate an output signal related to the determined value for the current, and provide the output signal to the display.

Claims

1. A method of measuring a current in a first current range and a second current range using a multi-meter, the method comprising:

receiving, at a first current input of a controller, a first signal from a first electrical current measuring circuit located between a first input terminal of the multi-meter and a second input terminal of the multi-meter, the first electrical current measuring circuit measuring electrical current in the first current range;

receiving, at a second current input of the controller, a second signal from a second electrical current measuring circuit located between the first input terminal of the multi-meter and the second input terminal of the multi-meter, the second electrical current measuring circuit measuring electrical current in the second current range;

comparing, using the controller, the first signal to a predetermined threshold value;

determining, using the controller, a value for the current being measured based on the first signal when the first signal is below the predetermined threshold value;

determining, using the controller, a value for the current being measured based on the second signal when the first signal is greater than or approximately equal to the predetermined threshold value;

generating, using the controller, an output signal related to the determined value for the current; and

providing the output signal to a display of the multi-meter to display the determined value for the current on the display.

2. The method of claim 1, further comprising

receiving an electrical property selection input from a user-interface;

receiving, at the controller, a third signal related to the electrical property selection;

determining, using the controller, a value for an electrical property based on the third signal; and

generating, using the controller, a second output signal related to the value for the electrical property.

3. The method of claim 2, wherein the electrical property is one of a voltage, a resistance, an inductance, a capacitance, a frequency, and a temperature.

4. The method of claim 1, wherein the predetermined threshold is between approximately 0.1 volts and approximately 0.5 volts.

5. The method of claim 1, wherein the value for the current being measured based on the first signal is less than or approximately equal to one ampere.

6. The method of claim 5, wherein the value for the current being measured based on the second signal is greater than or approximately equal to one ampere.

7. The method of claim 1, wherein the first signal and the second signal are voltages.

8. A method of measuring a current in a first current range or a second current range using a multi-meter, the method comprising:

receiving, at a first current input of a controller, a first signal from a first electrical current measuring circuit located between a first input terminal of the multi-meter and a second input terminal of the multi-meter, the first electrical current measuring circuit measuring electrical current in the first current range;

receiving, at a second current input of the controller, a second signal from a second electrical current measuring circuit located between the first input terminal of the multi-meter and the second input terminal of the multi-meter, the second electrical current measuring circuit measuring electrical current in the second current range;

comparing, using the controller, the first signal to a predetermined threshold value;

determining, using the controller, a value for the current being measured based on the first signal when the first signal is below the predetermined threshold value;

generating, using the controller, an output signal related to the determined value for the current; and

providing the output signal to a display of the multi-meter to display the determined value for the current on the display.

9. The method of claim 8, wherein the value for the current being measured based on the first signal is less than or approximately equal to one ampere.

10. The method of claim 8, wherein the first signal and the second signal are voltages.

11. The method of claim 8, further comprising

receiving an electrical property selection input from a user-interface;

receiving, at the controller, a third signal related to the electrical property selection;

determining, using the controller, a value for an electrical property based on the third signal; and

generating, using the controller, a second output signal related to the value for the electrical property.

12. A method of measuring a current in a first current range or a second current range using a multi-meter, the method comprising:

receiving, at a first current input of a controller, a first signal from a first electrical current measuring circuit located between a first input terminal of the multi-meter and a second input terminal of the multi-meter, the first electrical current measuring circuit measuring electrical current in the first current range;

receiving, at a second current input of the controller, a second signal from a second electrical current measuring circuit located between the first input terminal of the multi-meter and the second input terminal of the multi-meter, the second electrical current measuring circuit measuring electrical current in the second current range;

comparing, using the controller, the first signal to a predetermined threshold value;

determining, using the controller, a value for the current being measured based on the second signal when the first signal is greater than or approximately equal to the predetermined threshold value;

generating, using the controller, an output signal related to the determined value for the current; and

providing the output signal to a display of the multi-meter to display the determined value for the current on the display.

13. The method of claim 12, where the value for the current being measured based on the second signal is greater than or approximately equal to one ampere.

14. The method of claim 12, wherein the first signal and the second signal are voltages.