Abstract:
A capacitor test fixture for positioning capacitors under test includes a main body, a clamping section, an operating section, and a cover. The main body defines an opening, a plurality of receiving slots at the bottom of the opening to receive the capacitors, some positioning slots located at opposite sides of the opening, and a sliding slot. The clamping section includes a first hook, and the operating section includes a second hook corresponding to the first hook. The cover locates and fixes the clamping section and the operating section to the main body. The operating section functions when the second hook holds back the first hook, the capacitors under test are received within the receiving slots, and when the second hook releases the first hook, the clamping section secures and makes contact with the capacitors for testing.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The disclosure generally relates to mechanical devices, and more particularly to a capacitor test fixture and a test system employing the same. 
         [0003]    2. Description of the Related Art 
         [0004]    The capacitance of capacitors on a circuit board often needs to be tested to ensure that dependent circuits on the circuit board are working normally. However, the capacitance of capacitors mounted on the circuit board cannot be directly measured easily due to their small size. For example, some capacitors, such as chip capacitors, cannot be accessed by probes reliably because of the small package in which they are presented, which may result in test errors and inaccurate results. 
         [0005]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of a capacitor test fixture and test system employing the same can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the capacitor test fixture and test system employing the same. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment. 
           [0007]      FIG. 1  is a schematic and exploded view of a capacitor test fixture used in a test system, according to one embodiment of the disclosure. 
           [0008]      FIG. 2  is a schematic and assembled view of the capacitor test fixture shown in  FIG. 1  of the disclosure. 
           [0009]      FIG. 3  is an assembled cross-sectional view of the capacitor test fixture when securing and testing capacitors under test shown in  FIG. 2  of the disclosure. 
           [0010]      FIG. 4  is an assembled cross-sectional view of the capacitor test fixture when excluding the capacitors under test shown in  FIG. 3  of the disclosure. 
           [0011]      FIG. 5  is a circuit view of a test circuit of the test system of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]      FIG. 1  shows an exploded view of a capacitor test fixture  10  used in a test system (not shown), according to one embodiment of the disclosure. The test system is capable of measuring and obtaining the capacitance of different capacitors  30 , and is positioned in a housing (not shown). The capacitor test fixture  10  is received and is secured within the housing. 
         [0013]    Referring to  FIG. 2 , the capacitor test fixture  10  includes a main body  11 , two clamping sections  12 , two operating sections  13 , and two covers  14 . In this embodiment, the main body  11  is substantially a cuboid, and includes an operating surface  101  and a bottom surface  102  correspondingly parallel to the operating surface  101 . The operating surface  101  defines a large and substantially rectangular slot or opening (opening  111 ) at opposite sides of, and extending through, the main body  11 . 
         [0014]    The opening  111  defines a plurality of receiving slots  112  at the bottom surface of the opening  111 , and each receiving slot  112  has a different shape and size. In this embodiment, the shapes and sizes of the receiving slots  112  substantially match and correspond to those of the capacitors  30  under test. The receiving slots  112  are configured for receiving the capacitors  30  under test. 
         [0015]    The operating surface  101  further defines two positioning slots  113  and four sliding slots  114 . In this embodiment, the two positioning slots  113  are substantially rectangular and are symmetrically arranged about the opening  111 . The positioning slots  113  communicate with the opening  111  and are capable of receiving corresponding operating sections  13 . The four sliding slots  114  are substantially rectangular and each pair (of the two pairs of the sliding slots  114 ) flanks a positioning slot  113  of the two positioning slots  113 . In this embodiment, the opening  111  divides the operating surface  101  into two substantially similar parts, each part includes one positioning slot  113  and two sliding slots  114 , and the positioning slot  113  is parallel to the two sliding slots  114 . The main body  11  further defines a plurality of through mounting holes (mounting holes  115 ) adjacent to the edge of the operating surface  101 . 
         [0016]    The clamping sections  12  are substantially rectangular blocks, and each clamping section  12  includes a holding portion  121  which slopes downwards towards the opposing clamping section. The two holding portions  121  face each other, and the capacitors  30  under test are held immovably in place between the two holding portions  121 . Each clamping section  12  further includes two guiding posts  122  and two elastic portions  123 . The guiding posts  122  are effectively located behind the holding portions  121 , and function in support of them. The uncompressed length of the elastic portion  123  is greater than that of the corresponding post  122 . One end of the elastic portion  123  is removably assembled onto the corresponding guiding post  122 , and the other end is fixed on the sidewall of the corresponding sliding slot  114 . In this embodiment, each elastic portion  123  is a cylindrical spring. 
         [0017]    Each clamping section  12  further includes a handle  124  and a first hook  125 . The handle  124  is located on the upper surface of the clamping section  12 , and the first hook  125  is positioned between the guiding posts  122 . The two clamping sections  12  move back and forth along the corresponding sliding slots  114  by operating and moving the handles  124 , as to hold or release the capacitors  30  under test in the receiving slots  112 . 
         [0018]    Further referring to  FIGS. 3 and 4 , the buttons (operating sections  13 ) are substantially square in section and are removably received within the corresponding positioning slots  113 . Each operating section  13  includes a spring  131  and an integral second hook  132 . One end of the spring  131  is fixed in the operating section  13 , and the other end rests on the bottom of the positioning slot  113 , thereby, the operating sections  13  can move up and down in the positioning slots  113 . The second hooks  132  interact with the first hooks  125  to lock back the first hooks  125  and release them. 
         [0019]    In this embodiment, when the two handles  124  are moved away from each other in opposite directions, the clamping sections  12  slide along the sliding slots  114 , the first hooks  125  hold and fasten the corresponding second hooks  132 . Thus, the two clamping sections  12  are held back by the second hooks  132 , and the elastic portions  123  are compressed. The receiving slots  112  are thus exposed to hold and receive the capacitors  30  under test. When the capacitors  30  are received within the receiving slots  112 , the operating sections  13  can be pushed down into the positioning slots  113  to further compress the springs  131 , the first hooks  125  unfasten and separate the lock from the second hooks  132 . Thus, the clamping sections  12  move closer to each other under the action of the elastic force of the elastic portions  123 , until the holding portions  121  make contact with and secure the capacitors  30  under test. 
         [0020]    The covers  14  are flat for the main part and are mounted on the main body  11 . Each cover  14  defines a through hole  141  and a gap  142 . The through hole  141  aligns with the corresponding operating section  13 , so the operating section  13  is exposed and passes through the corresponding through hole  141 . In this embodiment, the gaps  142  are substantially rectangular and are aligned with the corresponding handles  124 . Thus, the handles  124  are configured for moving a short distance along the corresponding gaps  142 . 
         [0021]    The cover  14  further defines a plurality of screw holes  143  extending through the cover  14 , the screw holes  143  are aligned with the corresponding mounting holes  115  on the main body  11 . The screw holes  143  are configured for receiving the corresponding screws  144 , so that the covers  14  are fixed to the main body  11  through the screws  144 . 
         [0022]    Also referring to  FIG. 5 , the test circuit  20  includes a test unit  21 , a signal processing unit  22 , a signal displaying unit  23 , a capacitor C1, and two resistors R1 and R2. The test unit  21  can be an AD7150 integrated circuit and includes a power pin VDD, a ground pin GND, a first group of test pins CIN1 and EXC1, a second group of test pins CIN2 and EXC2, a clock pin SCL, a data pin SDA, and two output pins OUT1 and OUT2. 
         [0023]    In this embodiment, the power pin VDD is electrically connected to a power source VCC and is electrically connected to ground through the capacitor C1. The ground pin GND is electrically connected to ground. The capacitor  30  under test is electrically connected between the test pins CIN1 and EXC1 or the test pins CIN2 and EXC2 to test and obtain the capacitance of the capacitors  30  under test. 
         [0024]    The signal processing unit  22  can be a PIC1674 microcontroller and includes a group of data transmission pins RC1-RC4 and a group of data output pins RB4-RB7. In this embodiment, the data transmission pins RC1-RC4 are electrically connected to the output pins OUT2 and OUT1, the clock pin SCL and the data pin SDA, respectively. The data transmission pins RC3 and RC4 are electrically connected to the power source VCC through the resistors R1 and R2 respectively. The data output pins RB4-RB7 are electrically connected to the signal displaying unit  23 . The signal processing unit  22  is capable of processing test data from the test unit  21  to generate test results and outputting the test results to the signal displaying unit  23  through the data output pins RB4-RB7. The signal displaying unit  23  can be a MZLH04-12864 microchip to display the test results, such as capacitance of the capacitors  30  under test. 
         [0025]    Referring to  FIGS. 1-4 , in assembly, the operating sections  13  are received in the corresponding positioning slots  113 , and the clamping sections  12  are received within the corresponding positioning slots  113  and the sliding slots  114 . In detail, the holding portions  121  face toward each other, the first hooks  125  face toward the second hooks  132 , one end of the elastic portion  123  is assembled to the guiding post  122 , and the other end is fixed on the sidewall of the sliding slot  114 . The through holes  141  are aligned with the corresponding operating sections  13 , the handles  124  are aligned with and slide within the corresponding gaps  142 . The screw holes  143  are aligned with the mounting holes  115  on the main body  11 , and the screws  144  extend through the screw holes  143  and the mounting holes  155  to fix and assemble covers  14  to the main body  11 . 
         [0026]    To test the capacitors  30  under test, the two handles  134  are moved away from each other in opposite direction, the guiding posts  122  of the clamping sections  12  slide along the sliding slots  114 , and the first hooks  125  hold and fasten the corresponding second hooks  132 . Thus, the two clamping sections  12  are fixed, and the elastic portions  123  are compressed. The receiving slots  112  are exposed, and the capacitors  30  under test are received within corresponding receiving slots  112  according to their types and sizes. By pressing the operating sections  13  along the positioning slots  113 , the clamping sections  12  move close to each other under the action of the elastic force of the elastic portions  123 , and the holding portions  121  secure and contact the capacitors  30  under test, preventing the capacitors  30  movement. The test circuit  20  is powered on to measure the capacitance of the capacitors  30  under test, and the test results are displayed on the signal displaying unit  23 . 
         [0027]    In summary, the capacitor test fixture  10  can effectively fix the capacitors  30  under test and prevent the capacitors  30  movement by operating the handles  124  and the operating sections  13 . Moreover, the capacitor test fixture  10  has a simple structure and is easy for operation, which can quickly and efficiently test the capacitors  30  under test, even if the small chip capacitors. 
         [0028]    In the present specification and claims the word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. Further, the word “comprising” does not exclude the presence of other elements or steps than those listed. 
         [0029]    It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.