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AssigneeNone recorded
InventorXianhong Zhang
Estimating the term…
The present utility model provides a digital multi-meter that can not only; generate warning signal when the test probe is misplugged but also indicate the assigned socket before the probe is plugged in. The multi-meter contains a socket indicating a misplug warning circuit whose micro-control unit is connected with each measurement function switch via its terminals respectively. When any measurement function switch is closed and its corresponding socket is unclosed, the micro-control unit switches on the relevant LED to emit light via connected terminal in order to indicate the assigned docket. On the contrary, the micro-control unit switches off the LED to stop emitting light in order to indicated the proper operation. The multi-meter can indicate not only mis-operation after the probe has been plugged in but also the assigned socket before it so that it decreases the possibility of mis-operation and avoids damage effectively and elongates its working life.
A digital multi-meter, comprising a switch for voltage/Ohm, a switch for mA/uA testing, a switch for large current testing, and connecting jacks for said switches, wherein, further comprising a circuit for indicating inserted jack and warning wrong insertion, said circuit comprising:
Dependencies are inferred from the claim text.
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Cleaning arrangements; Filters: filters
Circuits for multi-testers , i.e. multimeters, e.g. for measuring voltage, current, or impedance at will: for digital multimeters
Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00: overload-protection arrangements or…
Measuring volume, volume flow, mass flow or liquid level
Term ended 5 Jul 2022 (estimated)
This invention relates to digital testing device, particularly, relates to a new type of digital multi-meter, which possesses an error prevention capability.
During the use of a multi-meter or other electronics test equipment, if the test leads are incorrectly inserted, this will damage the equipment. Based on experience in repairing damaged meters, over 50% of the cases are caused by the incorrect insertion of the test leads. As a result, some manufacturers added warning buzzers or other sound devices to alert the user that the meter has been damaged. Unfortunately, these warning devices are activated only after the equipment has been damaged, therefore it cannot prevent the meter from being damaged.
The objective of this new invention is to not only warn the user after the wrong insertion of the test lead but also indicate the correct place for user to insert the test lead.
FIG. 1. An example of a circuit diagram of the jack and warning system of a digital multi-meter.
FIG. 2. Another example of a circuit diagram of the jack and warning system of a digital multi-meter.
Digital multi-meter typically includes testing functions and testing function selection switches. The input analog signals received from the test lead are translated into digital signals via a digital (A/D) translation circuit and the result of the test is then shown on a liquid crystal display. In using the new digital multi-meter, there also includes an indicator to show the correct jack for the leads to be inserted and a circuit system to warn the user when a lead has been incorrectly inserted. The above are all connected to the Voltage/Ohm testing function, mA/uA testing function and large current testing function and the respective function switches.
The function switch, A/D translation circuit and liquid crystal display components are all understood by the respective technicians and these are not specifically associated with this new innovation. As a result, the mechanics of these components will not be elaborated any further in this document. Below, FIGS. 1 & 2 illustrate the make-up and mechanics of the lead jack indicator and warning circuit system.
FIG. 1. An example of a circuit diagram of the jack and warning system As shown in FIG. 1, the Voltage/Ohm testing function switch “K1”, the mA/uA testing function switch “K2”, the large current testing switch “K3”, the Voltage/Ohm testing jack “K4”, the mA/uA testing jack “K5”, and the large current testing jack switch “K6” are connected respectively to pins “2”, “3”, “6”, “7”, “8” and “9” of IC89C2051. The buzzer “Bz” is connected to pin “19”, LED1 (beside the V/ohm jack) to pin “16”, LED2 (beside the mA/uA jack) to pin “17” and LED3 (beside the A jack) to pin “18”. The crystal CX with capacitor C1 and C2 form an OSC circuit that generates a 4 MHz clock signal for IC89C2051 through pin4 and pin5. The resistor R1 and R2, the capacitor CE1, CE2 and C3 work together for supplying the working voltage and current to the IC.