CN217112515U - Inductance measuring device - Google Patents

Abstract

The utility model discloses an inductance measuring device, which comprises a measuring circuit, a key circuit, a main control microprocessor, a digital display unit and a buzzing circuit; the key circuit, the measuring circuit, the buzzing circuit and the digital display unit are respectively connected with the main control microprocessor; the measuring circuit is based on an inductance measuring circuit of a capacitance three-point oscillation method, and a main control microprocessor reads the frequency quantity of the measuring circuit and converts the frequency into the inductance quantity to finish inductance detection. The circuit is simple, the cost is low, and the device is easy to be combined with a production line.

Description

an inductance measuring device

technical field

The utility model belongs to the field of wire wound inductance, in particular to an inductance measuring device.

Background technique

In the inductance production line, most of the inductances are wound by automatic production lines. In the process of automatic production line winding and production line turnover, damage to the internal magnetic ring will inevitably occur, resulting in unqualified inductance, artificial sampling and Visual inspection will also have unqualified products leaking out, so it is necessary to measure the inductance one by one.

The traditional methods of measuring inductance include unbalanced bridge inductance measurement method and balanced bridge inductance measurement method. Modern inductance measurement equipment includes vector impedance measuring instrument and capacitive three-point oscillation method to measure inductance. The unbalanced bridge inductance measurement method and the balanced bridge inductance measurement method are slow in measurement, and the instrument is large in size; the vector impedance measuring instrument has complex circuit structure, bulky volume and high price, and is not suitable for automated inductance production lines. The capacitance three-point oscillation method to measure the inductance is to convert the inductance into the frequency to measure, the circuit is relatively simple, and it is easy to combine with the production line.

SUMMARY OF THE INVENTION

The technical problem to be solved by the utility model is to provide an inductance measuring device with relatively simple circuit and low cost.

An inductance measurement device of the utility model comprises a measurement circuit and a main control microprocessor; the measurement circuit is connected with the main control microprocessor, and the measurement circuit is an inductance measurement circuit based on a capacitance three-point oscillation method.

The measurement circuit includes a capacitor three-point oscillation circuit and an FPGA frequency divider. The capacitor three-point oscillation circuit includes capacitors C5, C6, C7-C9, an inductance LX1 to be measured, resistors R22-26, transistor T1 and transistor T2; capacitor C5 and capacitor C9 In series, the other end of capacitor C5 is connected to the collector of transistor T2, the midpoint of capacitor C5 and capacitor C9 is connected to the emitter of transistor T2, the other end of capacitor C9 is grounded, and capacitor C7 and C8 are connected in parallel to the base of transistor T2 and ground; the inductance LX1 to be tested is connected between Vcc and the collector of the transistor T2, and the resistor R24 is connected between the collector and the base of the transistor T2;

The midpoint of capacitor C5 and capacitor C9 is also connected to coupling capacitor C6, the other end of capacitor C6 is connected to the base of transistor T1, the emitter of transistor T1 is grounded through resistor R26, the collector of transistor T1 is connected to Vcc through resistor R23, and resistor R22 Connected between Vcc and the base of the transistor T1, the emitter of the transistor T1 is connected to the FPGA frequency divider; the FPGA frequency divider is connected to the input end of the main control microprocessor.

Further, an inductance measuring device of the present invention also includes a button circuit, which is connected to the main control microprocessor and is used to control the reading of the frequency of the measurement circuit by the main control microprocessor, when the button is not pressed. , the microprocessor port level is high. When the button is pressed, the level of the microprocessor port is pulled down to the ground, and the microprocessor begins to read the frequency of the measurement circuit.

Further, the button circuit includes resistance exclusion R20, resistance exclusion R21, capacitors C1-C4, and switches S1-S4; the resistance exclusion R20 and resistance exclusion R21 each include four resistors, and the switches S1-S4 are respectively connected with the resistance exclusion R21. Four resistors are connected in series, the other ends of the four switches are all grounded, and the four capacitors are respectively connected in series with the four resistors in the exclusion resistor R20 and then connected in parallel to the two ends of the four switches for anti-static leakage.

Further, an inductance measuring device of the present invention further includes a digital display unit for displaying the inductance value.

Further, an inductance measuring device of the present invention further includes a buzzer circuit, which is used to emit a buzzer sound when the measured inductance exceeds the set inductance threshold.

Beneficial effects: the capacitance three-point oscillation method adopted by the utility model is used for inductance measurement, the circuit is simple, the cost is low, and it is easy to be integrated with the automatic production line, and the manual measurement can be changed to collecting automatic trigger signals for automatic measurement in the later stage.

Description of drawings

Figure 1 is a block diagram of the present invention.

Figure 2 is a key circuit diagram.

Figure 3 is a measurement circuit diagram.

Fig. 4 is the main control microprocessor and peripheral circuit diagram.

Detailed ways

The utility model provides an inductance measuring device, as shown in FIG. 1 , comprising a measuring circuit, a button circuit, a main control microprocessor, a digital display unit and a buzzer circuit;

The button circuit, the measurement circuit, the buzzer circuit and the digital display unit are respectively connected with the main control microprocessor, and the button circuit is used to send a signal to start the measurement to the main control microprocessor;

The measurement circuit is based on the inductance measurement circuit of the capacitance three-point oscillation method. The main control microprocessor reads the frequency of the measurement circuit, and converts the frequency into the inductance to complete the inductance detection.

The digital display unit is used to display the inductance value;

Specifically, as shown in FIG. 2 , the button circuit includes resistance exclusion R20, resistance exclusion R21, capacitors C1-C4, and switches S1-S4. The resistance exclusion R20 and resistance exclusion R21 each include four resistors, and the switches S1-S4 are respectively It is connected in series with the four resistors in the exclusion resistor R21, the four capacitors are respectively connected in series with the four resistors in the exclusion resistance R20, and then connected in parallel to the two ends of the four switches, and the other ends of the four capacitors are all grounded. In this embodiment, the capacitors C1 to C4 are all 10 μF in size, the resistances in the exclusion R20 are all 10 KΩ, and the resistances in the exclusion R21 are all 1 KΩ.

As shown in Figure 3, the measurement circuit includes a capacitor three-point oscillation circuit and an FPGA frequency divider. The capacitor three-point oscillation circuit includes capacitors C5, C6, C7-C9, an inductance LX1 to be measured, resistors R22-26, and a transistor T1. and transistor T2;

The capacitor C5 and the capacitor C9 are connected in series, the other end of the capacitor C5 is connected to the collector of the transistor T2, the midpoint of the capacitor C5 and the capacitor C9 is connected to the emitter of the transistor T2, the other end of the capacitor C9 is connected to the ground, and the capacitor C7 and C8 are connected in parallel. Between the base of the transistor T2 and the ground;

The midpoint of capacitor C5 and capacitor C9 is also connected to coupling capacitor C6, the other end of capacitor C6 is connected to the base of transistor T1, the emitter of transistor T1 is grounded through resistor R26, the collector of transistor T1 is connected to Vcc through resistor R23, and resistor R22 It is connected between Vcc and the base of the transistor T1 to provide a bias voltage for the transistor T1, and the emitter of the transistor T1 is connected to the FPGA frequency divider; the FPGA frequency divider is connected to the input end of the main control microprocessor. The peripheral circuit of the main control microprocessor is shown in Figure 4.

The specific process of measuring the inductance of the utility model is as follows: the inductance to be measured is placed in the measuring circuit, the self-excited oscillation is formed in the measuring circuit, the oscillation frequency is taken from the emitter of the transistor T1, and after frequency division by the FPGA frequency divider, the main control microcomputer The processor reads the frequency division signal of the measuring circuit, the main control microprocessor calculates the actual frequency, and further calculates the inductance value according to the actual frequency, and the digital display unit displays the inductance value. The beeping circuit emits a beeping sound.

Claims (5)

1. The inductance measuring device is characterized by comprising a measuring circuit and a master control microprocessor;

the measuring circuit is connected with the master control microprocessor, and the measuring circuit is an inductance measuring circuit based on a capacitance three-point oscillation method;

the measuring circuit comprises a capacitance three-point type oscillating circuit and an FPGA frequency divider, wherein the capacitance three-point type oscillating circuit comprises capacitances C5, C6, C7-C9, an inductance LX1 to be measured, resistances R22-26, a transistor T1 and a transistor T2;

the capacitor C5 is connected in series with the capacitor C9, the other end of the capacitor C5 is connected to the collector of the transistor T2, the midpoint of the capacitor C5 and the capacitor C9 is connected to the emitter of the transistor T2, the other end of the capacitor C9 is grounded, and the capacitors C7 and C8 are connected between the base of the transistor T2 and the ground in parallel; the inductor LX1 to be tested is connected between Vcc and the collector of the transistor T2, and the resistor R24 is connected between the collector and the base of the transistor T2;

the midpoint between the capacitor C5 and the capacitor C9 is also connected with a coupling capacitor C6, the other end of the capacitor C6 is connected with the base of a transistor T1, the emitter of the transistor T1 is grounded through a resistor R26, the collector of the transistor T1 is connected with Vcc through a resistor R23, a resistor R22 is connected between Vcc and the base of a transistor T1, and the emitter of a transistor T1 is connected with an FPGA frequency divider; the FPGA frequency divider is connected with the input end of the master control microprocessor.

2. The inductance measuring device according to claim 1, further comprising a key circuit, wherein the key circuit is connected to the main control microprocessor.

3. The inductance measuring device according to claim 2, wherein the key circuit comprises a resistor R20, a resistor R21, capacitors C1-C4 and switches S1-S4;

the resistor exclusion R20 and the resistor exclusion R21 respectively comprise four resistors, the switches S1-S4 are respectively connected with the four resistors in the resistor exclusion R21 in series, the other ends of the four switches are respectively grounded, and the four capacitors are respectively connected with the four resistors in the resistor exclusion R20 in series and then respectively connected to two ends of the four switches in parallel.

4. The inductance measuring device according to claim 1, further comprising a digital display unit for displaying the inductance value.

5. The inductance measuring device according to claim 1, further comprising a buzzer circuit for sounding a buzzer when the measured inductance exceeds a set inductance threshold.

Images