CN218481578U - Test pencil - Google Patents
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- CN218481578U CN218481578U CN202221998913.3U CN202221998913U CN218481578U CN 218481578 U CN218481578 U CN 218481578U CN 202221998913 U CN202221998913 U CN 202221998913U CN 218481578 U CN218481578 U CN 218481578U
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Abstract
The utility model relates to a test pencil, include: a probe head; the touch point is connected with the probe and grounded; the diode is arranged between the probe and the touch point, the anode of the diode is connected with the probe, and the cathode of the diode is connected with the touch point; a first detection circuit including a first switching device connected between the probe and the diode; a second detection circuit including a second switching device connected between the diode and the touch point; a first light emitting diode; a second light emitting diode; and the control module is provided with a first port connected with the first switching device, a second port connected with the second switching device, a third port connected with the first light-emitting diode and a fourth port connected with the second light-emitting diode, and can control the first light-emitting diode and/or the second light-emitting diode to be conducted according to the detection results of the first port and the second port. The test pencil can realize the detection of the positive and negative electrodes of the direct current power supply and the zero line and the live line of the alternating current power supply.
Description
Technical Field
The utility model relates to an electrical tool technical field, in particular to test pencil.
Background
The test pencil, also called test pencil, is a kind of electrician tool used to test whether the wire is electrified or not. The pen body is provided with a neon bulb, and if the neon bulb shines during testing, the neon bulb indicates that the lead is electrified or is a fire wire of a passage.
The current test pencil can judge whether an object is electrified or not, and can also be used for judging whether an accessed power supply is alternating current or direct current, and when the test pencil is used for testing, if two poles in a neon bulb of the test pencil are both luminous, the alternating current is obtained; if only one of the two poles emits light, the direct current is generated; in addition, when the anode and the cathode of direct current are judged by the test pencil, the neon tube is observed to be thin, the front end is bright and is the cathode, and the rear end is bright and is the anode. However, the current test pencil still has the following limitations: 1. the zero line and the live line of the alternating current cannot be judged; 2. if the external light is too strong, the observation of the lightening of the neon tube is influenced, and an operator cannot clearly see whether the neon tube is lightened or not, so that the operator has a misjudgment condition and judges that the neon tube is electrified as non-electrified. Further improvements are needed for this purpose.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the first technical problem to above-mentioned prior art, provide a test pencil that can carry out the detection to the zero line and the live wire of alternating current.
The utility model discloses the second technical problem that will solve is to above-mentioned prior art, provides a test pencil that can reduce the result erroneous judgement.
The utility model provides a technical scheme that above-mentioned first technical problem adopted does: a test pencil, comprising:
a probe head;
the touch point is connected with the probe and grounded;
the method is characterized in that: the test pencil further comprises:
the diode is arranged between the probe and the touch point, the anode of the diode is connected with the probe, and the cathode of the diode is connected with the touch point;
a first detection circuit comprising a first switching device, a first end of the first switching device being connected between the probe head and a diode;
a second detection circuit including a second switching device, a first end of the second switching device being connected between the diode and the touch point;
a first light emitting diode;
a second light emitting diode; and
the control module is provided with a first port connected with the second end of the first switch device, a second port connected with the second end of the second switch device, a third port connected with the first light-emitting diode and a fourth port connected with the second light-emitting diode, and can control the third port and the fourth port to send out control signals according to detection results of the first port and the second port, so that the first light-emitting diode and/or the second light-emitting diode are controlled to be conducted.
Preferably, the first detection circuit further includes a first pull-up circuit, the first switching device is a first MOS transistor, a gate of the first MOS transistor forms a first end of the first switching device, a source of the first MOS transistor is grounded, and a drain of the first MOS transistor forms a second end of the first switching device and is connected to the first pull-up circuit.
In order to realize a pull-up effect, the first pull-up circuit comprises a first pull-up resistor, one end of the first pull-up resistor is connected with the drain electrode of the first MOS tube, and the other end of the first pull-up resistor is connected with a power supply.
Preferably, the second detection circuit further includes a second pull-up circuit, the second switching device is a second MOS transistor, a gate of the second MOS transistor forms a first end of the second switching device, a source of the second MOS transistor is grounded, and a drain of the second MOS transistor forms a second end of the second switching device and is connected to the second pull-up circuit.
In order to realize the pull-up effect, the second pull-up circuit comprises a second pull-up resistor, the other end of the second pull-up resistor is connected with the drain electrode of the second MOS tube, and the other end of the second pull-up resistor is connected with a power supply.
In order to avoid electric shock accidents, the circuit also comprises a first resistor and a third resistor, wherein the first resistor and the third resistor are arranged between the probe and the diode and between the diode and the touch point, the first resistor and the diode are used as a grid connection part of the first MOS tube, and the diode and the third resistor are used as a grid connection part of the second MOS tube.
The voltage division through first resistance and third resistance to make the electric current between detecting head and the earthing terminal reduce, so that the voltage of touch point is not big, thereby can effectively avoid taking place the electric shock accident.
In order to limit the working current of the first light-emitting diode and prevent the first light-emitting diode from being burnt out, the LED driving circuit further comprises a first current-limiting resistor connected with the first light-emitting diode in series, the other end of the first current-limiting resistor is connected with a third port of the control module, and the other end of the first light-emitting diode is grounded.
In order to limit the working current of the second light emitting diode and prevent the second light emitting diode from being burnt out, the LED driving circuit further comprises a second current limiting resistor connected with the second light emitting diode in series, the other end of the second current limiting resistor is connected with the fourth port of the control module, and the other end of the second light emitting diode is grounded.
To solve the second technical problem, the first light emitting diode and the second light emitting diode have different light emitting colors.
In order to realize the power supply to the control module, the control device also comprises a battery connected with the control module.
Compared with the prior art, the utility model has the advantages of: the first detection circuit and the second detection circuit are connected with the control module, when the positive electrode and the negative electrode of the direct current power supply are connected to the detection head and the touch point and the zero line or the live line of the alternating current power supply is connected to the detection head, the detection results of the first detection circuit and the second detection circuit are different, and therefore the control module can control the conduction of the first light emitting diode and/or the second light emitting diode according to the detection results of the first detection circuit and the second detection circuit. Therefore, the test pencil can realize the detection of the positive and negative electrodes of the direct current power supply and the zero line and the live line of the alternating current power supply, and is more practical.
Drawings
Fig. 1 is a circuit diagram of the test pencil according to the embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
As shown in fig. 1, the test pencil in the present embodiment includes a probe head 3 and a touch point 4. The probe 3 is grounded through the first resistor R1, the diode ZD1 and the third resistor R3 connected in series, and the touch point 4 is connected between the third resistor R3 and the ground GND.
The test pencil further comprises a first detection circuit 1, a second detection circuit 2, a first light emitting diode LED1, a second light emitting diode LED2 and a control module U1. Wherein the first detection circuit 1 includes a first switching device 11 connected between the probe 3 and the diode ZD1 and a first pull-up circuit 12 to which the first switching device 11 is connected; the second detection circuit 2 includes a second switching device 21 connected between the diode ZD1 and the touch point 4 and a second pull-up circuit 22 to which the second switching device 21 is connected; the control module U1 has a first port PA2 connected between the first pull-up circuit 12 and the first switching device 11, a second port PA5 connected between the second pull-up circuit 22 and the second switching device 21, a third port PWM3 connected to the first light emitting diode LED1, and a fourth port PC3 connected to the second light emitting diode LED2, and the control module U1 can enable the third port PWM3 and the fourth port PC3 to send out control signals according to the detection results of the first port PA2 and the second port PA5, thereby controlling the first light emitting diode LED1 and/or the second light emitting diode LED2 to be conducted. In the embodiment, the control module U1 is a single chip microcomputer of a model FT60F 011A-RB.
In this embodiment, the first switching device 11 is a first MOS transistor QP2, but a switching device such as a triode may also be used, a gate of the first MOS transistor QP2 is connected between the first resistor R1 and the diode ZD1, a source of the first MOS transistor QP2 is grounded, and a drain of the first MOS transistor QP2 is connected to the first pull-up circuit 12. In addition, the first pull-up circuit 12 includes a first pull-up resistor RL1, one end of the first pull-up resistor RL1 is connected to the drain of the first MOS transistor QP2, and the other end of the first pull-up resistor RL1 is connected to a power source VCC.
In this embodiment, the second switching device 21 is a second MOS transistor QP3, a gate of the second MOS transistor QP3 is connected between the diode ZD1 and the third resistor R3, a source of the second MOS transistor QP3 is grounded, and a drain of the second MOS transistor QP3 is connected to the second pull-up circuit 22. In addition, the second pull-up circuit 22 includes a second pull-up resistor RL2, the other end of the second pull-up resistor RL2 is connected to the drain of the second MOS transistor QP3, and the other end of the second pull-up resistor RL2 is connected to the power source VCC.
The test pencil further comprises a first current-limiting resistor RL connected with the first light-emitting diode LED1 in series, the other end of the first current-limiting resistor RL is connected with a third port PWM3 of the control module U1, and the other end of the first light-emitting diode LED1 is grounded. In addition, the test pencil further comprises a second current limiting resistor RR connected with the second light emitting diode LED2 in series, the other end of the second current limiting resistor RR is connected with a fourth port PC3 of the control module U1, and the other end of the second light emitting diode LED2 is grounded.
For the convenience of user identification, the first light emitting diode LED1 and the second light emitting diode LED2 have different light emitting colors. In this embodiment, the first light emitting diode LED1 is blue, and the second light emitting diode LED2 is red. The light sources with different colors can be distinguished more, so that the misjudgment condition caused by judging whether the light source is lightened or not in the prior art is reduced.
The electricity measuring meter further comprises a battery BAT connected with the control module U1, the voltage of the battery BAT is 4.5V, and the positive electrode and the negative electrode of the battery BAT are respectively connected with the power supply VCC and the grounding terminal.
The working process of the electricity meter in the embodiment is as follows:
the connection position between the drain electrode of the second MOS tube QP3 and the second pull-up circuit 22 is marked as point A, and the connection position between the drain electrode of the first MOS tube QP2 and the first pull-up circuit 12 is marked as point B;
1. when a direct-current power supply is detected, if the positive electrode of the direct-current power supply is connected to the probe 3 and the negative electrode of the direct-current power supply is connected to the touch point 4, the first MOS transistor QP2 in the first detection circuit 1 is cut off, the second MOS transistor QP3 in the second detection circuit 2 is conducted, and the voltage of the point B is 4.5V because the first MOS transistor QP2 is cut off; since the second MOS transistor QP3 is turned on, the voltage at the point a is 0V under the pull-up action of the second pull-up resistor RL2, and therefore the control module U1 sends a control signal to the fourth port PC3 to control the second light emitting diode LED2 to be turned on, i.e., to turn on the red light;
2. when the direct current power supply is to be detected, if the positive electrode of the direct current power supply is connected to the touch point 4 and the negative electrode of the direct current power supply is connected to the probe 3, the first MOS transistor QP2 in the first detection circuit 1 is turned on, the second MOS transistor QP3 in the second detection circuit 2 is turned off, and the voltage at the point B is 0V under the pull-up action of the first pull-up resistor RL1 because the first MOS transistor QP2 is turned on; and because the second MOS tube QP3 is cut off, the voltage of the point A is 4.5V; therefore, the control module U1 sends a control signal to the third port PWM3 to control the first light emitting diode LED1 to be turned on, i.e., to turn on the blue light;
3. when an alternating current power supply needs to be detected, assuming that a live wire of the alternating current power supply is connected to the probe 3, a hand touches the touch point 4, namely the probe 3 and the touch point 4 form a loop, and sinusoidal alternating current flows into the loop, the sinusoidal alternating current enables a first MOS tube QP2 in a first detection circuit 1 to be conducted at intervals, a second MOS tube QP3 in a second detection circuit 2 to be conducted at intervals, wherein the first MOS tube QP2 and the second MOS tube QP3 are in opposite states, the second MOS tube QP3 is cut off when the first MOS tube QP2 is conducted, the second MOS tube QP3 is conducted when the first MOS tube QP2 is cut off, so that voltages of a point A and a point B form a square wave at intervals, and a control module U1 sends a control signal to a third port PWM3 and/or a fourth port PC3 at intervals so as to control the conduction of the first light-emitting diode LED1 and the second light-emitting diode LED2, namely blue light and red light flicker;
4. when an alternating current power supply is detected, if a zero line of the alternating current power supply is connected to a probe 3, and a hand touches a touch point 4, a first MOS (metal oxide semiconductor) transistor QP2 in a first detection circuit 1 is conducted, a second MOS transistor QP3 in a second detection circuit 2 is cut off, and the first MOS transistor QP2 is conducted, so that the voltage of a point B is 0V under the pull-up action of a first pull-up resistor RL 1; and because the second MOS tube QP3 is cut off, the voltage of the point A is 4.5V; therefore, the control module U1 sends a control signal to the third port PWM3 to control the first light emitting diode LED1 to be turned on, i.e., to turn on the blue light.
Therefore, the test pencil in the embodiment can realize the detection of the direct current power supply and the alternating current power supply, and in addition, if the red light is on when the direct current power supply is detected, the probe 3 is judged to be connected with the positive pole of the direct current power supply at the moment, and the touch point 4 is connected with the negative pole of the direct current power supply; when the direct current power supply is detected, if the red light is on, the detector head 3 is judged to be connected with the negative electrode of the direct current power supply, and the touch point 4 is judged to be connected with the positive electrode of the direct current power supply; when the alternating current power supply is detected, if the blue lamp and the red lamp flicker, the detection head 3 is judged to be connected with a live wire of the alternating current power supply; when detecting the alternating current power supply, if the blue light is on, the probe 3 is judged to be connected with the zero line of the alternating current power supply at the moment. And because the lamps with different colors are used for replacing neon tubes to light, the occurrence of misjudgment can be effectively reduced.
Claims (10)
1. A test pencil, comprising:
a probe head (3);
the touch point (4) is connected with the probe (3) and is grounded;
the method is characterized in that: the test pencil further comprises:
the diode (ZD 1) is arranged between the detecting head (3) and the touch point (4), the anode of the diode (ZD 1) is connected with the detecting head (3), and the cathode of the diode (ZD 1) is connected with the touch point (4);
a first detection circuit (1) comprising a first switching device (11), a first terminal of said first switching device (11) being connected between said probe (3) and a diode (ZD 1);
a second detection circuit (2) comprising a second switching device (21), a first terminal of said second switching device (21) being connected between said diode (ZD 1) and a touch point (4);
a first light emitting diode (LED 1);
a second light emitting diode (LED 2); and
the control module (U1) is provided with a first port (PA 2) connected with the second end of the first switching device (11), a second port (PA 5) connected with the second end of the second switching device (21), a third port (PWM 3) connected with the first light-emitting diode (LED 1) and a fourth port (PC 3) connected with the second light-emitting diode (LED 2), and the control module (U1) can control the third port (PWM 3) and the fourth port (PC 3) to send out control signals according to detection results of the first port (PA 2) and the second port (PA 5), so that the first light-emitting diode (LED 1) and/or the second light-emitting diode (LED 2) are controlled to be conducted.
2. The test pencil of claim 1, wherein: the first detection circuit (1) further comprises a first pull-up circuit (12), the first switch device (11) is a first MOS (metal oxide semiconductor) transistor (QP 2), the grid electrode of the first MOS transistor (QP 2) forms a first end of the first switch device (11), the source electrode of the first MOS transistor (QP 2) is grounded, and the drain electrode of the first MOS transistor (QP 2) forms a second end of the first switch device (11) and is connected with the first pull-up circuit (12).
3. The test pencil of claim 2 wherein: the first pull-up circuit (12) comprises a first pull-up resistor (RL 1), one end of the first pull-up resistor (RL 1) is connected with the drain electrode of the first MOS transistor (QP 2), and the other end of the first pull-up resistor (RL 1) is connected with a power supply (VCC).
4. The test pencil of claim 2 wherein: the second detection circuit (2) further comprises a second pull-up circuit (22), the second switching device (21) is a second MOS transistor (QP 3), a gate of the second MOS transistor (QP 3) forms a first end of the second switching device (21), a source of the second MOS transistor (QP 3) is grounded, and a drain of the second MOS transistor (QP 3) forms a second end of the second switching device (21) and is connected to the second pull-up circuit (22).
5. The test pencil of claim 4, wherein: the second pull-up circuit (22) comprises a second pull-up resistor (RL 2), the other end of the second pull-up resistor (RL 2) is connected with the drain electrode of the second MOS tube (QP 3), and the other end of the second pull-up resistor (RL 2) is connected with a power supply (VCC).
6. The test pencil of claim 4, wherein: still including locating still being equipped with first resistance (R1) between detecting head (3) and diode (ZD 1) and locating third resistance (R3) between diode (ZD 1) and touch point (4), be as the grid junction with first MOS pipe (QP 2) between first resistance (R1) and diode (ZD 1), be as the grid junction with second MOS pipe (QP 3) between diode (ZD 1) and third resistance (R3).
7. The test pencil of any one of claims 1 to 6 wherein: the LED driving circuit also comprises a first current limiting Resistor (RL) connected with the first LED (LED 1) in series, the other end of the first current limiting Resistor (RL) is connected with a third port (PWM 3) of the control module (U1), and the other end of the first LED (LED 1) is grounded.
8. The test pencil of claim 7, wherein: the LED driving circuit also comprises a second current-limiting resistor (RR) connected with the second light-emitting diode (LED 2) in series, the other end of the second current-limiting resistor (RR) is connected with a fourth port (PC 3) of the control module (U1), and the other end of the second light-emitting diode (LED 2) is grounded.
9. The test pencil of claim 8 wherein: the first light emitting diode (LED 1) and the second light emitting diode (LED 2) have different light emitting colors.
10. The test pencil of any one of claims 1 to 6 wherein: the battery pack also comprises a Battery (BAT) connected with the control module (U1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221998913.3U CN218481578U (en) | 2022-07-29 | 2022-07-29 | Test pencil |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221998913.3U CN218481578U (en) | 2022-07-29 | 2022-07-29 | Test pencil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218481578U true CN218481578U (en) | 2023-02-14 |
Family
ID=85165600
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221998913.3U Active CN218481578U (en) | 2022-07-29 | 2022-07-29 | Test pencil |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218481578U (en) |
-
2022
- 2022-07-29 CN CN202221998913.3U patent/CN218481578U/en active Active
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