Small NTC (Negative Temperature Coefficient) thermistor with glass-sealed diode structure and preparation method thereof

Abstract

The invention relates to a small NTC (Negative Temperature Coefficient) thermistor with a glass-sealed diode structure and a preparation method thereof. The NTC thermistor is characterized in that two Dumet wires clamp an NTC thermo-sensitive chip; the exterior is encapsulated with a glass bulb; the total length is 7mm; the length of the glass bulb is 2.55mm; the external diameter is 1.35mm; after the glass bulb and the long Dumet wire are bent, the total width is 1.8mm; the space between the long Dumet wire and the short Dumet wire is 1.28mm; and the diameter of each Dumet wire is 0.3mm. The preparation method is as follows: preparing NTC thermo-sensitive ceramic according to an electronic ceramic preparation process; after printing a silver electrode through a silk screen, firing the electrode; cutting the electrode into the NTC thermo-sensitive chip; filling the NTC thermo-sensitive chip into the glass bulb through a graphite mould, clamping two ends by the two Dumet wires, and encapsulating at a high temperature; and bending the long Dumet wire along the root of the glass bulb, and cutting out the excessive part to obtain a product, wherein the total width is 1.8mm after the glass bulb and the long Dumet wire are bent. The small NTC thermistor with the glass-sealed diode structure is small in dimension and structure, low in production cost and easy to produce massively, and can be widely applied for a temperature sensor below phi 3mm to phi 4mm, with an epoxy encapsulation and case filling-sealing structure.

Description

technical field [0001] The invention relates to an NTC thermistor, in particular to a small glass-encapsulated diode structure NTC thermistor and a preparation method thereof. Background technique [0002] At present, there are three types of NTC thermistors that are common on the market: single-ended glass-encapsulated bead type, glass-encapsulated diode type with axial leads at both ends, and radial solder tab epoxy-encapsulated AT type. Single-ended glass-encapsulated bead type, radial soldering tab epoxy-encapsulated AT type have low production efficiency and low output. [0003] Both ends of the glass-sealed diode type NTC thermistor are axially drawn out. The DO35 glass-sealed diode structure thermal sensor is composed of two Dumet wires, a glass bulb and a diode-structured NTC thermal chip. First, a silk wire 3 The big end of the end face is put into the graphite mold upwards, and then the glass bulb 5 is loaded into the same graphite mold through tooling, wherein th...

AI Technical Summary

Problems solved by technology

After bending, its size is close to 3mm, and it cannot be used in epoxy-encapsulated and shell-encapsulated temperature sensors below φ4mm, and cannot meet the requirements of miniaturized temperature sensor devices.

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