Digital multi-meter

Patent metadata

Field	Value
Publication number	US-9568504-B2
Application number	US-201414212156-A
Country	US
Kind code	B2
Filing date	Mar 14, 2014
Priority date	Mar 15, 2013
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

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.

First claim

What is claimed is:

1. A multi-meter comprising:
a first input terminal;
a second input terminal;
a display;
a first current measuring circuit between the first input terminal and the second input terminal, the first current measuring circuit operable for measuring current in a first current range;
a second current measuring circuit between the first input terminal and the second input terminal, the second current measuring circuit operable for measuring current in a second current range; and
a controller including a first current measuring input, a second current measuring input, a processor, and a memory, the controller configured to
receive a first signal from the first current measuring circuit at the first current measuring input,
receive a second signal from the second current measuring circuit at the second current measuring input,
compare the first signal to a predetermined threshold value,
determine a value for a current being measured based on the first signal when the first signal is below the predetermined threshold value,
determine 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,
generate an output signal related to the determined value for the current, and
provide the output signal to the display.

2. The multi-meter of claim 1 , wherein the multi-meter is a hand-held multi-meter.

3. The multi-meter of claim 1 , further comprising a third input terminal, the controller further configured to
receive an electrical property selection input from a user-interface,
receive a third signal related to the electrical property selection,
determine a value for an electrical property based on the third signal, and
generate a second output signal related to the value for the electrical property.

4. The multi-meter of claim 3 , wherein the electrical property is one of a voltage, a resistance, an inductance, a capacitance, a frequency, and a temperature.

5. The multi-meter of claim 1 , wherein the predetermined threshold is between approximately 0.1 volts and approximately 5.0 volts.

6. The multi-meter of claim 1 , wherein the value for a current being measured based on the first signal is less than or approximately equal to one ampere.

7. The multi-meter of claim 6 , where the value for a current being measured based on the second signal is greater than or approximately equal to one ampere.

8. The multi-meter of claim 1 , wherein the controller is further configured to automatically switch between current measurement using the first current measuring circuit and current measurement using the second current measuring circuit.

9. The multi-meter of claim 1 , wherein the first current measuring circuit includes a first switch and a second switch.

10. The multi-meter of claim 9 , wherein the first switch and the second switch are connected in parallel.

11. The multi-meter of claim 9 , wherein the first switch and the second switch are in an ON state when the first signal is greater than or approximately equal to the predetermined threshold value.

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Cabot Benjamin Oliver Ryan
• Nguyen Evans H

Classifications

• G01R15/09 Primary

  Autoranging circuits · CPC title

• G01R15/125 Primary

  for digital multimeters · CPC title