JPH04209512A - Standard capacitor - Google Patents

Abstract

PURPOSE:To prevent a leak between terminals at hermetic terminal parts and to prevent the terminal parts from being corroded by a method wherein a hermetic substrate is mounted on a substrate and a silicone rubber whose dampproof effect is good is filled into a shielding sleeve fixed onto the hermetic substrate. CONSTITUTION:A plurality of hermetic terminals 6 on an insulating substrate 5 are connected to a hermetic substrate 4; a connector substrate 5 and upward faced pieces 9 on both ends of the substrate 4 are fixed to the inside of an upper-part case 1 by means of set screws 10. BNC connectors 11 are fitted into individual shielding sleeves 13; lug terminals 14 at their lower ends are soldered to the individual sleeves 13. Lead wires from the individual connectors 11 to the substrate 4 are shielded by means of the sleeves 13. Thereby, a capacity which is stable up to a high frequency can be obtained. When a silicone resin is filled into the sleeves 13, it is possible to prevent a leak between the terminals due to dew condensation at the hermetic terminals 6 and to prevent the hermetic terminals from being corroded so as to be insulated surely.

Description

[Detailed description of the invention]

[00011

[Field of Industrial Application] The present invention relates to a standard capacitor used for testing whether or not the measured value of a capacitor capacitance measuring device is accurate. 2. Description of the Related Art As mentioned above, a standard capacitor is a capacitor that serves as a standard for testing whether the measured value of a capacitance measuring device is correct. In other words, when determining whether or not the value measured by a capacitance measuring device of the capacitance of a manufactured capacitor is correct, measure the capacitance of a standard capacitor whose capacitance is known in advance, and if the values match, the measuring device I know it's correct. [0003] Therefore, standard capacitors are required to have good electrical characteristics, such as stable capacitance, low loss, and good frequency characteristics. [0004] Conventionally, air capacitors, silvered mica capacitors, fused crystal capacitors, and the like have been mainly used as capacitors with good electrical characteristics. [0005]

[Problems to be Solved by the Invention] Conventional standard capacitors as described above have problems such as being large and heavy, making it difficult to produce stable capacitances from small to large capacitances, and having poor frequency characteristics. [0006]

[Means for Solving the Problems] This invention has been made to solve the above-mentioned problems. A ceramic capacitor is mounted as a standard capacitor on a board provided in a case, and a ceramic capacitor is mounted as a standard capacitor on a board provided in a case. The object of the present invention is to provide a standard capacitor in which a hermetic substrate is attached to the capacitor, and a shielding sleeve fixed on the hermetic substrate is filled with silicone rubber having a good moisture-proofing effect. [0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. [0008] 1 is an upper outer case, 2 is a lower outer case, and 3 is an inner case installed inside the outer case 2, on which the hermetic board 4 is placed. 5 is an insulating substrate, and a plurality of hermetic terminals 6 on this substrate 5 are connected to the hermetic substrate 4. [0009] A ceramic capacitor 7 as a standard capacitor is mounted at the lower center of the hermetic board 4. [001018 is a connector board, and the second board 8 and the upwardly facing pieces 9 at both ends of the board 4 are fixed in the upper outer case 1 with set screws 10. [00111 A plurality of BNC connectors 11 are attached to the board 8, and each connector 11 has a lever 1.
2 is provided. The connector 11 is fitted into each shield sleeve 13 on the hermetic board 4, and the lug terminal 14 at the lower end thereof is soldered to each shield sleeve 13. Further, the upper outer case 1 is formed with openings 15 located directly above each of the connectors 11, respectively. [0012] The capacitance range of the capacitor 7 can cover a wide range of 1 opF to 1 μF by using a multilayer capacitor, and can be covered by combining one to four chip type or multilayer ceramic capacitors with lead terminals. [0013] The capacitance of the capacitor 7 can be adjusted to 10 pF by cutting the pattern on the substrate 5 and changing the stray capacitance. For other capacitances, for example, if you are trying to get the capacitance within the target 20.1%, you can stratify the basic capacitors aiming for a slightly lower capacitance at 0°2% intervals, and then 1/10
By combining with the 00 fine adjustment capacitor, it is possible to target a narrow range with good yield. [00141 Assembly has a structure in which a completed product can be obtained by assembling each component into the upper outer case 1 side. As a result, if the capacitance value is adjusted accurately just before covering the inner case 3, the desired capacitance can be obtained even in the finished product, and the assembly can be done more efficiently than the method of assembling the connector part and capacitor part separately. It is possible. [0015] By shielding the lead wire from the BNC connector 11 to the hermetic board 4 with the shield sleeve 13, stable capacitance can be obtained up to high frequencies. [0016] Silicone resin is cast inside the shield sleeve 13 to prevent leakage and corrosion between the terminals due to dew condensation at the hermetic terminal 6 portion. [0017] BNC connector 11 part is upper outer case 1
By covering it, it can withstand the impact of a fall. [0018] The inner case 3 is soldered to the hermetic board 4, and after the internal air is replaced with dry air through the hole 16, the hole 16 is closed with solder and the inside is sealed to prevent moisture absorption of the capacitor. This can be prevented and stable capacity can be obtained over a long period of time. [0019]

[Effects of the Invention] As described above, by mounting a ceramic capacitor on a board and incorporating it into a case, this invention can reduce the overall size, have good frequency characteristics, and provide stable capacitance from small to large capacitances. In particular, in this invention, a hermetic board is mounted on the board, and a shield sleeve fixed on the hermetic board is filled with silicone rubber that has a good moisture-proofing effect, thereby preventing leakage between terminals and corrosion due to dew condensation at the hermetic terminal part. This can be prevented and insulation can be ensured.

[Brief explanation of the drawing]

2. FIG. 1 is a plan view of the embodiment.

FIG. 2 is a front view of the embodiment.

FIG. 3 is a side view of the embodiment.

FIG. 4 is an exploded front view of the embodiment.

[Explanation of symbols]

4 Hermetic board 6 Hermetic terminal 7 Ceramic capacitor 13 Shield sleeve 14 Lug terminal

Claims (1)

[Claims] Claim 1: A ceramic capacitor is mounted as a standard capacitor on a board provided in a case, a hermetic board is mounted on the board, and a silicone rubber with good moisture-proofing effect is installed in a shielding sleeve fixed on the hermetic board. A standard capacitor characterized by being filled with.