JPS59184866A - Short-circuit determining system - Google Patents

Abstract

PURPOSE:To discriminate easily a short state as an oscillation frequency variation by incorporating a short part of a circuit element in a frequency determining part of a high frequency oscillating circuit as an impedance. CONSTITUTION:Contact leads 11, 12 of an oscillating circuit 10 are made to contact with conductive patterns A, B of a printed circuit to which capacitors C1, C2 and C3 are connected in parallel. The impedance across the contact leads 11,12 constitutes a determining part of an oscillation frequency of the oscillating circuit 10. For instance, if the capacitor C2 is in a short state, when the contact leads 11, 12 are made to contact with the part just under the capacitor C2, the oscillation frequency of the oscillating circuit 10 becomes the highest value, and a short part can be determined. A UHF band consists of the oscillation frequency of the oscillating circuit 10 therefore, it can be discriminated enough even if the interval of the capacitor C1 and C2 is about 1cm.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for monitoring short-circuit conditions in particular circuit sections or circuit elements in electronic circuits. Conventionally, continuity measuring means such as so-called testers have been used for this purpose, but in certain circuits, it is difficult to determine short-circuit points using such means. It is often possible to complete the implementation with just one implementation.

For example, as shown in Fig. 1, if capacitors Ci, C2°C3, diode Dl, coil L1 are connected in parallel to the printed pattern conductive paths of ■ and ■, and a socket or connector P is connected to the support, For example, if one of the circuit elements is faulty and exhibits a short-circuit condition, what can be done to measure continuity as described above? If you remove each part one by one and check for shorts individually, it is completely impossible to discover the situation. t74, sockets, connectors, etc., are not visible to the naked eye, making it extremely difficult to detect pattern shorts. These 7 yote situations are tentatively l/1
It cannot be determined even if an L ohmmeter with a sensitivity of 000 ohms is used.

The present invention utilizes a phenomenon in electronic circuits in which the oscillation frequency of the LIHF oscillator circuit fluctuates widely due to subtle changes in the oscillation constant. Therefore, it is incorporated into the generator circuit as an inductor with a short circuit path. Two contact leads are provided in connection with this oscillator circuit, and when these leads are brought into contact with both sides of the parts on the short line, the oscillator circuit will display a certain unique frequency, except for the short circuit. Knowing this frequency in advance, determine the short circuit. Figure 2 shows the principle of the present invention, and ■ and ■ indicate printed circuit conductive patterns similar to those described in connection with Figure 1. For example, three capacitors c1. Assume that c2 and C3 are connected. 1O is the 400 MHz oscillation circuit, 11.12 is the contact lead extending from the 7th circuit,
13 is a frequency counter for reading the oscillation frequency. J
The Aj wave number 13 may be a well-known one. In FIG. 2, it is assumed that capacitor C2 is now in a short-circuit state. It is assumed that the lead rods 11 and 12 are brought into contact just below the capacitor C1. In this case, an inductor (coil) corresponding to the route indicated by 14 is inserted into the oscillation circuit. Of course, in this case, the capacitors C, C3 and the equivalent circuit of the printed pattern are also affected. In this figure, the display on the frequency counter 13 is because the inductance, ie, the short circuit route, is at its minimum when the lead is placed just below the shorted capacitor C2.

Display the highest (high frequency value). Oscillation frequency UHF
Since the distance between capacitors C1 and C2 is
Even if a-b) is about Icm, sufficient discrimination is possible. Before actually using the invention, first cut the ends of the two lead rods.1. Knowing the frequency display at that time, the seventh frequency I
I learned from my judgment that when a part approaches MI-1z or below, it moves 7 yots.

FIG. 3 shows a complete implementation of the oscillation circuit 10 shown in FIG.

11 and 12 are 1M+21.25wR copper lead rods, 1
5 is an impedance forming the route 14 in FIG. The coaxial cable 16i is connected to the frequency counter 13, and the oscillation frequency is read out. This oscillator is 405. when the impedance 15 is Z=O+j(+(Ω)).
The light is adjusted so that it oscillates at 0.0 Iz.

[Brief explanation of drawings]

Figures 1 and 2. The figure is a schematic diagram used to determine how to use the principle of the present invention, and FIG. 3 is a detailed circuit diagram of some of the elements shown in FIG. indicates the frequency Carentan. Figure 1

Claims (1)

[Claims] Determination and determination of short-circuit conditions in any of a plurality of parallel-connected circuit elements or parts In the current method, the above-mentioned short-circuit impedance is incorporated into the oscillation frequency determining part of the high-frequency oscillation circuit, and the above-mentioned The above method is characterized in that the short section is determined.