JPS6318930Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a test device for detecting deterioration and manufacturing defects in bridge-connected diodes. Defective states of bridge diodes due to manufacturing or deterioration include large forward drop of the element (diode chip), large connection resistance and disconnection between the element and terminals, large reverse leakage current of the element, especially between each terminal (AC There are short circuits between terminals, DC terminals, between 4 terminals for a single-phase full waveform, and between 5 terminals for a 3-phase full waveform, and reverse connections of each element. Normally, each of these phenomena is tested using a separate test method to determine pass/fail. The present invention provides a testing device suitable for auxiliary monitoring during the above-mentioned pass/fail judgment, or for re-checking already judged non-defective products, and can easily detect the occurrence of any of the above-mentioned defective states with a single test. It was designed to do so. This will be explained below using the drawings. FIG. 1 is a circuit diagram of an embodiment of the present invention. In the figure, 1 is a reference bridge diode, (hereinafter referred to as a reference element) 2 is a bridge diode to be measured (hereinafter referred to as an element to be measured), and 3 and 4 are the elements 1, 2. One of the light emitting elements 3 is connected between the positive DC output terminals and between the negative terminals of the reference bridge diode. ) is connected to the DC output positive terminal side of the bridge diode to be measured, and the other light emitting element 4 is connected in opposite polarity to the one light emitting element 3. 3' and 4' are light receiving elements such as phototransistors, AL is an abnormality alarm circuit, 5 and 6 are test current carrying resistors with the same impedance,
7 and 8 are defective element conduction current suppressing resistors having the same impedance, and PW is an AC power supply. In addition,
Diode chips S1 to S4 and D1 to D4 are diode chips a and b are DC output terminals, and c and d are AC input terminals. In the figure, when voltage is applied from the AC test power supply PW, if the device under test 2 is a normal product that exhibits the same characteristics as the reference device 1, the voltage between the positive (+) and negative (-) terminals of both devices will be Since no voltage difference is generated and the light emitting elements 3 and 4 do not emit light, a signal indicating that the terminals of the light receiving elements 3' and 4' are in an open state is sent to the abnormality alarm circuit AL. If any abnormality exists in the device under test 2, the voltage between the positive and negative terminals of the device under test 2 will drop, resulting in a voltage difference between the positive terminals or between the negative terminals with respect to the reference device 1. Since the light emitting elements 3 and 4 are energized and emit light, and the light receiving elements 3' and 4' are energized, a signal is sent to the abnormality alarm circuit AL to reduce the impedance that allows current to flow between the light receiving elements. Incidentally, when diode D1 is open and AC power supply PW has the polarity shown, PW - diode D3 - resistor 5 -
A current flows through the path of light emitting element 4 - diode S1 - resistor 8 - PW, and light emitting element 4 emits light. When diode D3 is open, current flows through power supply PW, diode S3, light emitting diode 3, resistor 5, diode D1, resistor 7, and PW, causing light emitting element 3 to emit light. Furthermore bridge diode 2
When the DC output terminals a and b are short-circuited, the power supply PW-
Current flows through the path of diode S3 - light emitting element 3 - terminals a-b - light emitting element 4 - diode S1 - resistor 8 - PW, and both light emitting elements 3 and 4 emit light. These operations are shown in Table 1.

[Table] (* Lighting status marked with ○)
In addition, the abnormality alarm circuit AL has an amplification and signal holding circuit if necessary, and ultimately a buzzer, chime, indicator light, and in some cases (such as in the case of automatic testing equipment or sorting equipment), a corresponding electronic circuit or relay. A predetermined abnormality detection operation can be performed by the contact circuit. That is, the present invention applies the same voltage to the AC terminals of both the reference element and the measured element, and compares the rectified voltage waveforms generated between the DC output terminals.
When the voltage difference is greater than the forward voltage of the light emitting elements, one or both of the light emitting elements become conductive, and the state in which they emit light is used to detect an abnormality. In other words, in this invention, if an individual diode of the bridge diode to be measured is abnormal, the AC power supply
One half-wave output of the power supply PW is used to make one light-emitting element emit light, and in the case of a short circuit between the AC input terminal or DC output terminal, both light-emitting elements are made to emit light by the full-wave output of the power supply PW. This has the advantage that abnormalities can be distinguished by the state of the light emitted. Note that a photothyristor or the like can also be used as the light emitting element. Although the present invention has been described above using an example of a single-phase full-wave diode, it is obvious that it can be similarly applied to other multi-phase bridge elements such as a three-phase bridge. As is clear from the above explanation, according to the present invention, the presence or absence of various characteristic defects can be detected with a single measurement, so it can be used for re-checking non-defective products or attached to an individual characteristic testing device such as a curve tracer to measure the curve of each measuring element. It has great practical effects, such as being suitable for checking for short-circuit phenomena between AC terminals that cannot be detected by tracer patterns, or for checking for defects that may have been overlooked due to carelessness during individual sorting.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of one embodiment of the present invention. In the figure, 1... reference bridge diode, 2... bridge diode to be measured, 3, 4... light emitting element,
3', 4'... Light receiving element, 5, 6... Test current carrying resistance, 7, 8... Current suppressing resistor, AL... Alarm circuit, PW... AC power supply.

Claims (1)

[Scope of utility model registration request] A light emitting element is connected between the DC output positive terminals and between the negative terminals of the reference bridge diode and the measured bridge diode, respectively, and the one light emitting element is connected to the DC output positive terminal side of the reference bridge diode. is an anode (anode), the cathode (cathode) is connected to the direct current output positive terminal side of the bridge diode to be measured, and the other light emitting element is connected in opposite polarity to the one light emitting element. A closed circuit is formed by connecting the AC terminals of each of the bridge diodes to the same power source, and abnormality detection is performed using the light emitting state of one or both of the light emitting elements. Tsuji diode test equipment.