CN201666932U

CN201666932U - Short circuit detector

Info

Publication number: CN201666932U
Application number: CN2010201019036U
Authority: CN
Inventors: 王红波
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-01-25
Filing date: 2010-01-25
Publication date: 2010-12-08
Anticipated expiration: 2020-01-25

Abstract

The utility model discloses a short circuit detector comprising a drive circuit and a detecting circuit, wherein the detecting circuit is electrically connected with a linear display circuit and comprises a magnetic sensitive element A, a differential amplifier A electrically connected with the magnetic sensitive element A, a magnetic sensitive element B, a differential amplifier B electrically connected with the magnetic sensitive element B, a direct current component elimination circuit electrically connected with the differential amplifiers A and B and a differential amplifier C electrically connected with the direct current component elimination circuit, wherein the differential amplifier C is respectively electrically connected to positive and negative semi-cycle linear display circuits through direct current component elimination, clutter filtering and high frequency interference circuits; the magnetic sensitive element A is arranged at the end of a detecting pen; and the magnetic sensitive element B is arranged 8-12mm above the end of the detecting pen. The detector can more accurately and faster locate any short circuit point with loop feature.

Description

The short circuit detecting instrument

Technical field

The utility model relates to a kind of electronic detecting device, particularly a kind of short circuit detecting instrument.

Background technology

Electronics industry PCB and PCBA make produce and use in exist poor short circuit to need to repair, existing technologies by impedance ratio, method location short dots such as voltage drop measurement, current direction detection, there are defectives such as accuracy rate is low, efficient is low in above method; Or be applied on the short-circuit loop with output currents such as sine wave, square waves, by the inductance probe sensed current signal, thereby determine road electric current flow path, the location short dot, this inducing method is if exist capacitive element in the short-circuit loop, to form the by-passing signal interference and can't accurately find short dot, thereby use limited.

Summary of the invention

In order to address the above problem, the purpose of this utility model is to provide a kind of accuracy rate height, efficient short circuit detecting instrument high, that not influenced by capacitive element.

The technical scheme that the invention for solving the technical problem adopted is: the short circuit detecting instrument, comprise driving circuit, circuit for detecting, circuit for detecting is electrically connected with linear display circuit, linear display circuit just comprises, the linear display circuit of negative half period, driving circuit comprises D.C. regulated power supply, the pressure regulation current-limiting circuit that is electrically connected with D.C. regulated power supply, the electric current input switch that is electrically connected with the pressure regulation current-limiting circuit, the pressure that is electrically connected with the electric current input switch drags down switch, drag down switch gauge tap conducting that is electrically connected respectively and the waveform generator that ends with electric current input switch and pressure, electric current input switch and pressure drag down and are electrically connected with drive output between the switch, described circuit for detecting comprises magneto sensor A, the differential amplifier A that is electrically connected with magneto sensor A, magneto sensor B, the differential amplifier B that is electrically connected with magneto sensor B, with differential amplifier A, the elimination DC component circuit that B is electrically connected, the differential amplifier C that is electrically connected with elimination DC component circuit, differential amplifier C just is being electrically connected to respectively through eliminating DC component and filtering clutter and high-frequency interferencing circuit, the linear display circuit of negative half period, described magneto sensor A is located at the end of detecting pen, and magneto sensor B is located at the above 8-12 millimeter place, end of detecting pen.

Technique scheme also can have following improvement project: described magneto sensor A, magneto sensor B are hall sensor or other similar magneto sensor; Described detecting pen is provided with light emitting diode lamp or other similar display device that is used to show detection signal.

The beneficial effects of the utility model are: owing to adopt double magneto sensor to detect, one magneto sensor testing environment magnetic field, another magneto sensor testing environment magnetic field and drive current magnetic field, subtract each other to eliminate environmental magnetic field and disturb, drive signal is exported with square wave, so that the capacitive bypass current pulse width is narrow than short circuit reversion pulse width, come distinguish short-circuit electric current and capacitor loop electric current by comparing pulse width, the square wave output drive signal, negative half period is forced ground connection by internal circuit with output point voltage, eliminate capacitive effect in the test loop, the signal positive-negative half-cycle shows with two-way moment, eliminate the common mode interference of circuit and external environment condition, the difference amplitude is represented the signal intensity power, thereby determine short dot, environmental magnetic field disturbs and the shunt capacitance influence so the utility model efficiently solves, and makes that the induction by current pattern can be more accurately, locate the short dot of any loopback diagnostic more quickly.

Description of drawings

The utility model is described in further detail below in conjunction with drawings and Examples.

Fig. 1 is a job step process flow diagram of the present utility model;

Fig. 2 is a driving circuit block scheme of the present utility model;

Fig. 3 is the circuit diagram that drive signal of the present utility model produces part;

Fig. 4 is the circuit block diagram of detecting pen of the present utility model;

Fig. 5 is the circuit theory diagrams of detecting pen of the present utility model.

Embodiment

Referring to figs. 1 through Fig. 5, the utility model short circuit detecting instrument, comprise driving circuit 1, circuit for detecting 2, circuit for detecting 2 is electrically connected with linear display circuit 3, linear display circuit 3 just comprises, the linear display circuit 31 of negative half period, 32, linear display circuit is by the LM3914 point, line shows chip and light emitting diode is formed, driving circuit 1 comprises D.C. regulated power supply 4, the pressure regulation current-limiting circuit 5 that is electrically connected with D.C. regulated power supply 4, the electric current input switch 6 that is electrically connected with pressure regulation current-limiting circuit 5, the pressure that is electrically connected with electric current input switch 6 drags down switch 7, drag down switch 7 gauge tap conducting that is electrically connected respectively and the waveform generator 8 that ends with electric current input switch 6 and pressure, the pressure regulation current-limiting circuit is by the pressure regulation of adjustable three-terminal voltage-stabilizing pipe, the current-limiting resistance current limliting, electric current input switch 6 and pressure drag down and are electrically connected with drive output 9 between the switch 7, described circuit for detecting 2 comprises magneto sensor A21, the differential amplifier A 22 that is electrically connected with magneto sensor A21, magneto sensor B23, the differential amplifier B24 that is electrically connected with magneto sensor B23, with differential amplifier A 22, the elimination DC component circuit 25 that B24 is electrically connected, the differential amplifier C26 that is electrically connected with elimination DC component circuit 25, eliminate the DC component circuit by electric capacity, resistive isolation bypass DC component, differential amplifier C26 just is being electrically connected to respectively through eliminating DC component and filtering clutter and high-frequency interferencing circuit 27, the linear display circuit 31 of negative half period, 32, filtering clutter and high-frequency interferencing circuit are made up of the RC filtering circuit, described magneto sensor A21 is located at the end of detecting pen, and magneto sensor B23 is located at the above 8-12 millimeter place, end of detecting pen.

Technique scheme also can have following improvement project.Described magneto sensor A21, magneto sensor B23 are hall sensor or other similar magneto sensor.Described detecting pen is provided with light emitting diode lamp or other similar display device that is used to show detection signal.The detecting pen has Presentation Function, and detected signal intensity goes up directly in the detecting pen and shows.Described light emitting diodde desplay device can change to other similar display device, and hall sensor also can change to other similar magneto sensor.

Principle of work of the present utility model: export a drive signal by pulse-generating circuit, drive signal is connected to the two ends of short-circuit loop from drive output 9, make the pulse drive signal short-circuit loop of flowing through, produce stronger electromagnetic wave, detect the electromagnetic wave that short-circuit loop gives off by the detecting pen.The detecting pen adopts the dual inductor detecting, magneto sensor A detecting environmental magnetic field and drive signal magnetic field, and magneto sensor B detects environmental magnetic field, and two signal subtractions obtain not having the drive signal magnetic field detecting value of environment magnetic interference, are the electromagnetic wave that detects.During detecting,, promptly be traceable to the track of drive current, thereby find out the current path that normal circuit should not exist, detect short dot along with strong electromagnetic wave radiation signal mobile detection pen.

The utility model drive signal is exported with square wave, so that the capacitive bypass current pulse width is narrow than short circuit reversion pulse width, comes distinguish short-circuit electric current and capacitor loop electric current by comparing pulse width.The signal positive-negative half-cycle shows with two-way moment, eliminates the common mode interference of circuit and external environment condition, and the difference amplitude is represented the signal intensity power.

Claims

1. short circuit detecting instrument, comprise driving circuit (1), circuit for detecting (2), circuit for detecting (2) is electrically connected with linear display circuit (3), linear display circuit (3) just comprises, the linear display circuit (31 of negative half period, 32), driving circuit (1) comprises D.C. regulated power supply (4), the pressure regulation current-limiting circuit (5) that is electrically connected with D.C. regulated power supply (4), the electric current input switch (6) that is electrically connected with pressure regulation current-limiting circuit (5), the pressure that is electrically connected with electric current input switch (6) drags down switch (7), drag down switch (7) gauge tap conducting that is electrically connected respectively and the waveform generator (8) that ends with electric current input switch (6) and pressure, electric current input switch (6) and pressure drag down and are electrically connected with drive output (9) between the switch (7), it is characterized in that: described circuit for detecting (2) comprises magneto sensor A (21), the differential amplifier A (22) that is electrically connected with magneto sensor A (21), magneto sensor B (23), the differential amplifier B (24) that is electrically connected with magneto sensor B (23), with differential amplifier A, B (22,24) the elimination DC component circuit (25) of Dian Lianjieing, the differential amplifier C (26) that is electrically connected with elimination DC component circuit (25), differential amplifier C (26) just is being electrically connected to respectively through eliminating DC component and filtering clutter and high-frequency interferencing circuit (27), the linear display circuit (31 of negative half period, 32), described magneto sensor A (21) is located at the end of detecting pen, and magneto sensor B (23) is located at the above 8-12 millimeter place, end of detecting pen.

2. short circuit detecting instrument according to claim 1 is characterized in that: described magneto sensor A (21), magneto sensor B (23) are hall sensor.

3. short circuit detecting instrument according to claim 1 is characterized in that: described detecting pen is provided with the light emitting diode lamp that is used to show detection signal.