STM32-based resistance, inductance and capacitance measuring circuit

Abstract

The utility model relates to the technical field of resistance, inductance and capacitance measurement, in particular to an STM32-based resistance, inductance and capacitance measurement circuit, which comprises a control module, a channel simulation selection module, a resistance measurement module, an inductance measurement module and a capacitance measurement module. Resistance, inductance and capacitance value measurement and output with an automatic range are realized, and subsequent debugging, maintenance, expansion and upgrading are also facilitated. The resistance measurement module, the inductance measurement module and the capacitance measurement module output corresponding frequencies through an oscillating circuit, so that the control module can calculate the measured numerical value of the RLC, and the measurement precision is improved; and the channel simulation selection module realizes automatic range switching and is convenient to use.

Description

Technical Field

[0001] The utility model relates to the technical field of resistance, inductance and capacitance measurement, in particular to a resistance, inductance and capacitance measurement circuit based on STM32. Background Art

[0002] Modern electronic products are developing towards multifunctionality, miniaturization, and minimal power consumption. Currently, a wide variety of instruments are available on the market for measuring the RLC parameters of electronic components, each with its own unique methods and advantages and disadvantages. However, conventional electronic component measurement instruments often suffer from the inability to automatically switch ranges and low measurement accuracy.

[0003] Therefore, it is necessary to design a resistance, inductance and capacitance measurement circuit based on STM32 to realize automatic range switching and improve measurement accuracy. Summary of the Invention

[0004] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a resistance, inductance and capacitance measurement circuit based on STM32 to achieve automatic range switching and improve measurement accuracy.

[0005] To achieve the above object, the utility model is a resistance-inductance-capacitance measurement circuit based on STM32, including a control module, a channel simulation selection module, a resistance measurement module, an inductance measurement module, and a capacitance measurement module, wherein the digital differential signal output interface one, the digital differential signal output interface two, and the communication interface of the control module are respectively connected with the digital differential signal input interface one, the digital differential signal input interface two, and the communication interface of the channel simulation selection module in sequence, the capacitance signal interface of the channel simulation selection module is connected with the signal interface of the capacitance measurement module, the resistance signal interface of the channel simulation selection module is connected with the signal interface of the resistance measurement module, and the inductance signal interface of the channel simulation selection module is connected with the signal interface of the inductance measurement module.

[0006] The control module includes a main control chip, a display chip, an indicator light, a resistor, a sliding rheostat, a capacitor, a crystal oscillator, a terminal, and a button. The digital differential signal output interface 1, the digital differential signal output interface 2, and the communication interface of the control module are respectively connected to pins 68, 69, and 67 of the main control chip in sequence. Pins 23, 24, and 25 of the main control chip are respectively connected to one end of button 1, one end of button 2, and one end of button 3. Pin 30 of the main control chip is connected in series with resistor 1 and then connected to the cathode of indicator light 1. Pin 31 of the main control chip is connected in series with resistor 2 and then connected to the cathode of indicator light 2. Pin 32 of the main control chip is connected in series with resistor 1 and then connected to the cathode of indicator light 2. After the third resistor, it is connected to the cathode of indicator light three. The anode of indicator light three is divided into three ways and respectively connected to the VCC power supply, the anode of indicator light two, and the anode of indicator light one. Pin 81 of the main control chip is divided into two ways and respectively connected to pin 7 of the display chip and pin 2 of terminal one. Pin 82 of the main control chip is divided into two ways and respectively connected to pin 8 of the display chip and pin 3 of terminal one. Pin 83 of the main control chip is divided into two ways and respectively connected to pin 9 of the display chip and pin 4 of terminal one. Pin 84 of the main control chip is divided into two ways and respectively connected to pin 10 of the display chip and pin 5 of terminal one. Pin 85 of the main control chip is divided into two ways and respectively connected to pin 11 of the display chip. The main control chip No. 86 pin is divided into two ways and connected to the No. 12 pin of the display chip and the No. 7 pin of the terminal. The main control chip No. 87 pin is divided into two ways and connected to the No. 13 pin of the display chip and the No. 8 pin of the terminal. The main control chip No. 88 pin is divided into two ways and connected to the No. 14 pin of the display chip and the No. 9 pin of the terminal. The main control chip No. 55 pin, No. 56 pin and No. 57 pin are connected to the No. 4 pin, No. 5 pin and No. 6 pin of the display chip respectively. The No. 1 pin of the terminal is divided into four ways and connected to the VCC power supply end, one end of the sliding rheostat, the No. 2 pin and the No. 15 pin of the display chip respectively. Pin 3 of the display chip is connected to the sliding end of the sliding rheostat 1, pin 12 of the main control chip is divided into two ways and is respectively connected to one end of the crystal oscillator and one end of the capacitor 7, pin 13 of the main control chip is divided into two ways and is respectively connected to the other end of the crystal oscillator and one end of the capacitor 10, pin 14 of the main control chip is divided into two ways and is respectively connected to one end of the resistor 17 and one end of the capacitor 11, the other end of the resistor 17 is connected to the 3.3V power supply end, the other end of the sliding rheostat 1, the other end of the button 1, the other end of the button 2, the other end of the button 3, pin 1 and pin 16 of the display chip, pin 94 of the main control chip, the other end of the capacitor 7, the other end of the capacitor 10, and the other end of the capacitor 11 are grounded.

[0007] The channel analog selection module includes an analog switch. The digital differential signal input interface 1, the digital differential signal input interface 2, the communication interface, the capacitance signal interface, the resistance signal interface, and the inductance signal interface of the channel analog selection module are respectively connected to pins 10, 9, 13, 12, 14, and 15 of the analog switch. Pin 16 of the analog switch is connected to the VCC power supply terminal, and pins 6 and 8 of the analog switch are grounded.

[0008] The model of the main control chip is STM32F103, the model of the display chip is LCD1602, and the model of the analog switch is CD4052.

[0009] The resistance measurement module includes a time base chip, a resistor, a capacitor, a sliding rheostat, and a terminal. The signal interface of the resistance measurement module is connected to pin 3 of time base chip three, pin 5 of time base chip three is connected to one end of capacitor nine, pin 6 of time base chip three is divided into three paths and respectively connected to pin 2 of time base chip three, one end of capacitor twelve, and one end of resistor sixteen, the other end of resistor sixteen is connected to pin 1 of terminal three, pin 7 of time base chip three is divided into three paths and respectively connected to one end of resistor twelve, one end of resistor thirteen, and pin 2 of terminal three, the other end of resistor thirteen is divided into three paths and respectively connected to the VCC power supply, pin 4, and pin 8 of time base chip three, the other end of resistor twelve is connected to the sliding end of sliding rheostat three, one end of sliding rheostat three is connected to one end of resistor ten, the other end of resistor ten, the other end of capacitor nine, the other end of capacitor twelve, and pin 1 of time base chip three are grounded.

[0010] The inductance measurement module includes a time base chip, a resistor, a capacitor, a sliding rheostat, a transistor, and a terminal. The signal interface of the inductance measurement module is connected to pin 3 of the time base chip one, pin 5 of the time base chip one is connected to one end of the capacitor five, pin 6 of the time base chip one is divided into four paths and respectively connected to pin 2 of the time base chip one, one end of the resistor four, one end of the resistor eight, and the collector of the transistor two. The other end of the resistor four is divided into two paths and respectively connected to the VCC power supply end and pin 2 of the terminal two. The other end of the resistor eight is divided into two paths and respectively connected to the base of the transistor two and one end of the capacitor two. The other end of the capacitor two is divided into four paths and respectively connected to one end of the capacitor one, one end of the capacitor six, one end of the resistor nine, and the collector of the transistor two. The emitter of transistor one is connected, the other end of capacitor one is divided into four paths and is respectively connected to one end of resistor six, one end of resistor seven, the collector of transistor one, and pin 1 of terminal two; the base of transistor one is divided into two paths and is respectively connected to the positive electrode of electrolytic capacitor three and one end of sliding rheostat two; the other end of resistor seven is connected to one end of capacitor four, the other end of resistor six is connected to the sliding end of sliding rheostat two; pin 4 of time base chip one is divided into two paths and is respectively connected to the VCC power supply end and pin 8 of time base chip one; the negative electrode of electrolytic capacitor three, the other end of capacitor four, the other end of capacitor five, the other end of capacitor six, the other end of resistor nine, pin 1 of time base chip one, and the emitter of transistor two are grounded.

[0011] The capacitance measurement module includes a time base chip, a resistor, a capacitor, a sliding rheostat, and a terminal. The signal interface of the capacitance measurement module is connected to pin 3 of the time base chip 2, pin 5 of the time base chip 2 is connected to one end of capacitor 8, pin 6 of the time base chip 2 is divided into three paths and respectively connected to pin 2 of the time base chip 2, one end of resistor 15, and pin 2 of terminal 4. The other end of resistor 15 is connected in series with resistor 14 and then connected to the sliding end of sliding rheostat 4. Pin 7 of the time base chip 2 is divided into two paths and respectively connected to one end of resistor 11 and one end of sliding rheostat 4. The other end of resistor 11 is divided into three paths and respectively connected to the VCC power supply, pin 4, and pin 8 of the time base chip 2. The other end of capacitor 8, pin 1 of the time base chip 2, and pin 1 of terminal 4 are grounded.

[0012] The models of the time base chip 1, the time base chip 2 and the time base chip 3 are NE555.

[0013] Compared with the prior art, the utility model adopts a modular design to realize automatic range measurement and output of resistance, inductance and capacitance values, and is also convenient for subsequent debugging, maintenance, and expansion and upgrading; the resistance measurement module, the inductance measurement module, and the capacitance measurement module output corresponding frequencies through an oscillation circuit, so that the control module calculates the measured values of RLC and improves measurement accuracy; the channel simulation selection module realizes automatic range switching, which is easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a circuit diagram of the utility model.

[0015] Figure 2 This is a circuit diagram of the control module of the utility model.

[0016] Figure 3 This is the circuit diagram of the channel simulation selection module of the utility model.

[0017] Figure 4 This is the circuit diagram of the resistance measurement module of the present utility model.

[0018] Figure 5 This is the circuit diagram of the inductance measurement module of the utility model.

[0019] Figure 6 This is the circuit diagram of the capacitance measurement module of the utility model. DETAILED DESCRIPTION

[0020] The present invention will now be further described with reference to the accompanying drawings.

[0021] See also Figure 1 The utility model is a resistance, inductance and capacitance measurement circuit based on STM32, including a control module, a channel simulation selection module, a resistance measurement module, an inductance measurement module, and a capacitance measurement module. The digital differential signal output interface 1, the digital differential signal output interface 2, and the communication interface of the control module 1 are respectively connected to the digital differential signal input interface 1, the digital differential signal input interface 2, and the communication interface of the channel simulation selection module 2. The capacitance signal interface of the channel simulation selection module 2 is connected to the signal interface of the capacitance measurement module 5. The resistance signal interface of the channel simulation selection module 2 is connected to the signal interface of the resistance measurement module 3. The inductance signal interface of the channel simulation selection module 2 is connected to the signal interface of the inductance measurement module 4.

[0022] See also Figure 2The control module 1 includes a main control chip, a display chip, an indicator light, a resistor, a sliding resistor, a capacitor, a crystal oscillator, a terminal, and a button. The digital differential signal output interface 1, the digital differential signal output interface 2, and the communication interface of the control module 1 are respectively connected to pins 68, 69, and 67 of the main control chip U2A. Pins 23, 24, and 25 of the main control chip U2A are respectively connected to one end of button 1 S1, one end of button 2 S2, and one end of button 3 S3. Pin 30 of the main control chip U2A is connected in series with resistor 1 R1 and then to the cathode of indicator light 1 DS1. Pin 31 of the main control chip U2A is connected in series with resistor 2 R2 and then to the cathode of indicator light 2 D The cathode of S2 is connected, the 32nd pin of the main control chip U2A is connected in series with the resistor R3, and then connected to the cathode of the indicator light DS3. The anode of the indicator light DS3 is divided into three ways and respectively connected to the VCC power supply, the anode of the indicator light DS2, and the anode of the indicator light DS1. The 81st pin of the main control chip U2A is divided into two ways and respectively connected to the 7th pin of the display chip U3 and the 2nd pin of the terminal. The 82nd pin of the main control chip U2A is divided into two ways and respectively connected to the 8th pin of the display chip U3 and the 3rd pin of the terminal. The 83rd pin of the main control chip U2A is divided into two ways and respectively connected to the 9th pin of the display chip U3 and the 4th pin of the terminal. The 84th pin of the main control chip U2A is divided into two ways and respectively connected to the 10th pin of the display chip U3 and the 10th pin of the terminal. Connected to pin 10 of display chip U3 and pin 5 of terminal 1, pin 85 of main control chip U2A is divided into two ways and connected to pin 11 of display chip U3 and pin 6 of terminal 1 respectively, pin 86 of main control chip U2A is divided into two ways and connected to pin 12 of display chip U3 and pin 7 of terminal 1 respectively, pin 87 of main control chip U2A is divided into two ways and connected to pin 13 of display chip U3 and pin 8 of terminal 1 respectively, pin 88 of main control chip U2A is divided into two ways and connected to pin 14 of display chip U3 and pin 9 of terminal 1 respectively, pin 55, pin 56 and pin 57 of main control chip U2A are connected to pin 11 of display chip U3 and pin 6 of terminal 1 respectively, Pins 4, 5, and 6 are connected. Pin 1 of terminal 1 is divided into four paths and connected to the VCC power supply terminal, one end of the sliding rheostat RP1, and pins 2 and 15 of the display chip U3. Pin 3 of the display chip U3 is connected to the sliding end of the sliding rheostat RP1. Pin 12 of the main control chip U2A is divided into two paths and connected to one end of the crystal oscillator Y1 and one end of the capacitor C7. Pin 13 of the main control chip U2A is divided into two paths and connected to the other end of the crystal oscillator Y1 and one end of the capacitor C10. Pin 14 of the main control chip U2A is divided into two paths and connected to one end of the resistor R17 and one end of the capacitor C11. The other end of the resistor R17 is connected to 3.Connect the 3V power supply terminal, the other end of the sliding resistor RP1, the other end of the button 1 S1, the other end of the button 2 S2, the other end of the button 3 S3, pins 1 and 16 of the display chip U3, pin 94 of the main control chip U2A, the other end of capacitor 7 C7, the other end of capacitor 10 C10, and the other end of capacitor 11 C11 to ground.

[0023] In control module 1, the main control chip U2A is an STM32F103, boasting a wealth of on-chip resources, including a DMA controller, a CAN controller, a USB controller, a watchdog timer, multiple timers, and multiple parallel I / O interfaces. Functions such as range conversion, frequency calculation, and output display are implemented using the pin definitions of the main control chip U2A and its on-chip interrupt system, timers, and I / O functions. Display chip U3 is responsible for interface display. A 1602 LCD display offers high resolution and strong anti-interference capabilities. Buttons S1, S2, and S3 are used to switch between resistance, inductance, and capacitance ranges. Indicator lights DS1, DS2, and DS3 display the operating status of the resistance, inductance, and capacitance ranges. Terminal 1 R5 is a 10k resistor used to pull up the level. When the main control chip U2A does not send a signal, the pin is at a high level. The function of the sliding resistor RP1 is to adjust the V0 voltage, thereby changing the contrast of the display screen. The contrast is lowest when the power is connected. The function of the crystal oscillator Y1 is to generate a reference clock signal.

[0024] See also Figure 3 The channel analog selection module 2 includes an analog switch. The digital differential signal input interface 1, the digital differential signal input interface 2, the communication interface, the capacitance signal interface, the resistance signal interface, and the inductance signal interface of the channel analog selection module 2 are respectively connected to pins 10, 9, 13, 12, 14, and 15 of the analog switch U1. Pin 16 of the analog switch U1 is connected to the VCC power supply terminal, and pins 6 and 8 of the analog switch U1 are grounded.

[0025] The model of analog switch U1 is CD4052. Analog switch U1 is used to change the range. Pins 10 and 9 of analog switch U1 are two-way digital differential signal inputs. The analog signal is controlled according to the two-way differential digital signal of the main control module 1. Combined with the logic judgment control channel selection, the switching of resistance, inductance and capacitance range is realized, and the static power consumption is very low.

[0026] See also Figure 4The resistance measurement module 3 includes a time base chip, a resistor, a capacitor, a sliding rheostat, and a terminal. The signal interface of the resistance measurement module 3 is connected to the No. 3 pin of the time base chip U6, the No. 5 pin of the time base chip U6 is connected to one end of the capacitor C9, the No. 6 pin of the time base chip U6 is divided into three paths and respectively connected to the No. 2 pin of the time base chip U6, one end of the capacitor C12, and one end of the resistor R16. The other end of the resistor R16 is connected to the No. 1 pin of the terminal P2, and the No. 7 pin of the time base chip U6 is divided into three paths and respectively connected to the No. 2 pin of the time base chip U6, one end of the capacitor C12, and one end of the resistor R16. The other end of the resistor R16 is connected to the No. 1 pin of the terminal P2. It is connected to one end of resistor 12 R12, one end of resistor 13 R13, and pin 2 of terminal 3 P2. The other end of resistor 13 R13 is divided into three paths and connected to the VCC power supply, pin 4 and pin 8 of time base chip 3 U6 respectively. The other end of resistor 12 R12 is connected to the sliding end of sliding rheostat 3 RP3. One end of sliding rheostat 3 RP3 is connected to one end of resistor 10 R10. The other end of resistor 10 R10, the other end of capacitor 9 C9, the other end of capacitor 12 C12, and pin 1 of time base chip 3 U6 are grounded.

[0027] Timer chip U6 is an NE555. It also includes resistor R10, resistor R12, resistor R13, resistor R16, and capacitor C12, forming a multivibrator circuit. Using the pulse counting method, the multivibrator circuit calculates the resistance being measured by counting the frequency of the oscillation output. Terminal P2 is used to connect the component being measured.

[0028] See also Figure 5The inductance measurement module 4 includes a time base chip, a resistor, a capacitor, a sliding rheostat, a transistor, and a terminal. The signal interface of the inductance measurement module 4 is connected to pin 3 of the time base chip U4, pin 5 of the time base chip U4 is connected to one end of capacitor C5, pin 6 of the time base chip U4 is divided into four paths and respectively connected to pin 2 of the time base chip U4, one end of resistor R4, one end of resistor R8, and the collector of transistor Q2. The other end of resistor R4 is divided into two paths and respectively connected to the VCC power supply end and pin 2 of terminal P1. The other end of resistor R8 is divided into two paths and respectively connected to the base of transistor Q2 and one end of capacitor C2. The other end of capacitor C2 is divided into four paths and respectively connected to one end of capacitor C1, one end of capacitor C6, one end of resistor R9, and the collector of transistor Q1. The emitter is connected, the other end of capacitor C1 is divided into four paths and is respectively connected to one end of resistor R6, one end of resistor R7, the collector of transistor Q1, and pin 1 of terminal P1. The base of transistor Q1 is divided into two paths and is respectively connected to the positive electrode of electrolytic capacitor C3 and one end of sliding rheostat RP2. The other end of resistor R7 is connected to one end of capacitor C4, and the other end of resistor R6 is connected to the sliding end of sliding rheostat RP2. Pin 4 of timing chip U4 is divided into two paths and is respectively connected to the VCC power supply end and pin 8 of timing chip U4. The negative electrode of electrolytic capacitor C3, the other end of capacitor C4, the other end of capacitor C5, the other end of capacitor C6, the other end of resistor R9, pin 1 of timing chip U4, and the emitter of transistor Q2 are grounded.

[0029] The timer chip U4 is an NE555. It also includes transistors Q1 and Q2, rheostat RP2, resistors R4, R6, R7, R8, R9, capacitors C1, C2, electrolytic capacitors C3, C4, C5, and C6, forming a three-point capacitor oscillator circuit. This circuit adheres to the "emitter-radius-reflector" principle and meets the phase balance requirement for self-oscillation. The frequency of the oscillator output is used to calculate the inductance being measured. Terminal P1 is used to connect the component being measured.

[0030] See also Figure 6The capacitance measurement module 5 includes a timing chip, a resistor, a capacitor, a sliding rheostat, and a terminal. The signal interface of the capacitance measurement module 5 is connected to pin 3 of the timing chip U5, pin 5 of the timing chip U5 is connected to one end of capacitor C8, pin 6 of the timing chip U5 is divided into three paths and respectively connected to pin 2 of the timing chip U5, one end of resistor R15, and pin 2 of terminal P3. The other end of resistor R15 is connected in series with resistor R14 and then connected to the sliding end of sliding rheostat RP4. Pin 7 of the timing chip U5 is divided into two paths and respectively connected to one end of resistor R11 and one end of sliding rheostat RP4. The other end of resistor R11 is divided into three paths and respectively connected to the VCC power supply, pin 4, and pin 8 of the timing chip U5. The other end of capacitor C8, pin 1 of the timing chip U5, and pin 1 of terminal P3 are grounded.

[0031] The second timer chip, U5, is an NE555. It, along with rheostat RP4, resistor R11, resistor R14, resistor R15, and capacitor C8, form a multivibrator circuit. The measured capacitance is calculated by calculating the frequency of the oscillation output. Terminal P3 is used to connect the component under test.

[0032] The resistance measuring range of the utility model is 100Ω-1MΩ, the inductance measuring range is 100uH-100mH, the capacitance measuring range is 100pf-10000pf, and automatic range conversion is realized.

[0033] The utility model adopts a modular design to realize the measurement and output of resistance, inductance and capacitance values in an automatic range, which is also convenient for subsequent debugging, maintenance and expansion and upgrading; the resistance measurement module, inductance measurement module and capacitance measurement module output corresponding frequencies through an oscillation circuit, so that the control module can calculate the measured values of RLC and improve the measurement accuracy; the channel simulation selection module realizes automatic range switching, which is easy to use.

Claims

1. A resistance, inductance and capacitance measurement circuit based on STM32, including a control module, a channel simulation selection module, a resistance measurement module, an inductance measurement module, and a capacitance measurement module, characterized in that: The digital differential signal output interface 1, the digital differential signal output interface 2, and the communication interface of the control module (1) are connected to the digital differential signal input interface 1, the digital differential signal input interface 2, and the communication interface of the channel analog selection module (2) in sequence, respectively; the capacitance signal interface of the channel analog selection module (2) is connected to the signal interface of the capacitance measurement module (5); the resistance signal interface of the channel analog selection module (2) is connected to the signal interface of the resistance measurement module (3); and the inductance signal interface of the channel analog selection module (2) is connected to the signal interface of the inductance measurement module (4).

2. A resistance, inductance and capacitance measurement circuit based on STM32 according to claim 1, characterized in that: The control module (1) includes a main control chip, a display chip, an indicator light, a resistor, a sliding rheostat, a capacitor, a crystal oscillator, a terminal, and a button. The digital differential signal output interface 1, the digital differential signal output interface 2, and the communication interface of the control module (1) are respectively connected to pins 68, 69, and 67 of the main control chip (U2A). Pins 23, 24, and 25 of the main control chip (U2A) are respectively connected to one end of button 1 (S1), one end of button 2 (S2), and one end of button 3 (S3). Pin 30 of the main control chip (U2A) is connected in series with resistor 1 (R1) and then connected to the cathode of indicator light 1 (DS1). Pin 31 of the main control chip (U2A) is connected in series with the cathode of indicator light 1 (DS1). After connecting resistor 2 (R2) in series, it is connected to the cathode of indicator light 2 (DS2). After connecting resistor 3 (R3) in series, pin 32 of the main control chip (U2A) is connected to the cathode of indicator light 3 (DS3). The anode of indicator light 3 (DS3) is divided into three paths and respectively connected to the VCC power supply, the anode of indicator light 2 (DS2), and the anode of indicator light 1 (DS1). Pin 81 of the main control chip (U2A) is divided into two paths and respectively connected to pin 7 of the display chip (U3) and pin 2 of terminal 1. Pin 82 of the main control chip (U2A) is divided into two paths and respectively connected to pin 8 of the display chip (U3) and pin 3 of terminal 1. Pin 83 of the main control chip (U2A) is divided into two paths and respectively connected to pin 9 of the display chip (U3). Pin 1 of the main control chip (U2A) is connected to pin 10 of the display chip (U3) and pin 5 of terminal 1. Pin 85 of the main control chip (U2A) is connected to pin 11 of the display chip (U3) and pin 6 of terminal 1 in two ways. Pin 86 of the main control chip (U2A) is connected to pin 12 of the display chip (U3) and pin 7 of terminal 1 in two ways. Pin 87 of the main control chip (U2A) is connected to pin 13 of the display chip (U3) and pin 8 of terminal 1 in two ways. Pin 88 of the main control chip (U2A) is connected to pin 14 of the display chip (U3) and pin 9 of terminal 1 in two ways. Pin 55, pin 56 and pin 57 of the main control chip (U2A) are connected to pin 4, pin 5 and pin 6 of the display chip (U3) respectively. Pin 1 of terminal 1 is divided into four paths and connected to the VCC power supply end, one end of the sliding rheostat 1 (RP1), pin 2 and pin 15 of the display chip (U3). Pin 3 of the display chip (U3) is connected to the sliding end of the sliding rheostat 1 (RP1). Pin 12 of the main control chip (U2A) is divided into two paths and connected to one end of the crystal oscillator (Y1) and one end of capacitor seven (C7). Pin 13 of the main control chip (U2A) is divided into two paths and connected to the other end of the crystal oscillator (Y1) and one end of capacitor ten (C10).Pin 14 of the main control chip (U2A) is connected in two ways to one end of resistor 17 (R17) and one end of capacitor 11 (C11). The other end of resistor 17 (R17) is connected to the 3.3V power supply terminal. The other end of sliding rheostat 1 (RP1), the other end of button 1 (S1), the other end of button 2 (S2), the other end of button 3 (S3), pin 1 and pin 16 of the display chip (U3), pin 94 of the main control chip (U2A), the other end of capacitor 7 (C7), the other end of capacitor 10 (C10), and the other end of capacitor 11 (C11) are grounded.

3. A resistance, inductance and capacitance measurement circuit based on STM32 according to claim 1, characterized in that: The channel analog selection module (2) includes an analog switch. The digital differential signal input interface 1, the digital differential signal input interface 2, the communication interface, the capacitance signal interface, the resistance signal interface, and the inductance signal interface of the channel analog selection module (2) are respectively connected to pins 10, 9, 13, 12, 14, and 15 of the analog switch (U1). Pin 16 of the analog switch (U1) is connected to the VCC power supply terminal. Pins 6 and 8 of the analog switch (U1) are grounded.

4. A resistance, inductance and capacitance measurement circuit based on STM32 according to claim 2 or 3, characterized in that: The model of the main control chip (U2A) is STM32F103, the model of the display chip (U3) is LCD1602, and the model of the analog switch (U1) is CD4052.

5. A resistance, inductance and capacitance measurement circuit based on STM32 according to claim 1, characterized in that: The resistance measurement module (3) includes a time base chip, a resistor, a capacitor, a sliding rheostat, and a terminal. The signal interface of the resistance measurement module (3) is connected to pin 3 of the time base chip three (U6), pin 5 of the time base chip three (U6) is connected to one end of capacitor nine (C9), pin 6 of the time base chip three (U6) is divided into three paths and respectively connected to pin 2 of the time base chip three (U6), one end of capacitor twelve (C12), and one end of resistor sixteen (R16), the other end of resistor sixteen (R16) is connected to pin 1 of terminal three (P2), and pin 7 of the time base chip three (U6) is divided into three paths and respectively connected to pin 2 of the time base chip three (U6), one end of capacitor twelve (C12), and one end of resistor sixteen (R16). The other end of resistor sixteen (R16) is connected to pin 1 of terminal three (P2), and pin 7 of the time base chip three (U6) is divided into three paths and respectively connected to pin 2 of the time base chip three (U6), one end of capacitor twelve (C12), and one end of resistor sixteen (R16). It is connected to one end of resistor twelve (R12), one end of resistor thirteen (R13), and pin 2 of terminal three (P2). The other end of resistor thirteen (R13) is divided into three paths and connected to the VCC power supply, pin 4 and pin 8 of time base chip three (U6) respectively. The other end of resistor twelve (R12) is connected to the sliding end of sliding rheostat three (RP3). One end of sliding rheostat three (RP3) is connected to one end of resistor ten (R10). The other end of resistor ten (R10), the other end of capacitor nine (C9), the other end of capacitor twelve (C12), and pin 1 of time base chip three (U6) are grounded.

6. A resistance, inductance and capacitance measurement circuit based on STM32 according to claim 1, characterized in that: The inductance measurement module (4) includes a time base chip, a resistor, a capacitor, a sliding rheostat, a transistor, and a terminal. The signal interface of the inductance measurement module (4) is connected to pin 3 of the time base chip (U4), pin 5 of the time base chip (U4) is connected to one end of capacitor five (C5), and pin 6 of the time base chip (U4) is divided into four paths and connected to pin 2 of the time base chip (U4), one end of resistor four (R4), one end of resistor eight (R8), The collector of transistor 2 (Q2) is connected, the other end of resistor 4 (R4) is divided into two paths and connected to the VCC power supply terminal and pin 2 of terminal 2 (P1) respectively, the other end of resistor 8 (R8) is divided into two paths and connected to the base of transistor 2 (Q2) and one end of capacitor 2 (C2) respectively, the other end of capacitor 2 (C2) is divided into four paths and connected to one end of capacitor 1 (C1), one end of capacitor 6 (C6), one end of resistor 9 (R9), one end of transistor 1 (Q1) The emitter is connected, the other end of capacitor 1 (C1) is divided into four paths and connected to one end of resistor 6 (R6), one end of resistor 7 (R7), the collector of transistor 1 (Q1), and pin 1 of terminal 2 (P1). The base of transistor 1 (Q1) is divided into two paths and connected to the positive electrode of electrolytic capacitor 3 (C3) and one end of sliding rheostat 2 (RP2). The other end of resistor 7 (R7) is connected to one end of capacitor 4 (C4), and the other end of resistor 6 (R6) is connected to the positive electrode of electrolytic capacitor 3 (C3) and one end of sliding rheostat 2 (RP2). The end is connected to the sliding end of sliding rheostat 2 (RP2), pin 4 of time base chip 1 (U4) is divided into two paths and respectively connected to the VCC power supply end and pin 8 of time base chip 1 (U4), the negative electrode of electrolytic capacitor 3 (C3), the other end of capacitor 4 (C4), the other end of capacitor 5 (C5), the other end of capacitor 6 (C6), the other end of resistor 9 (R9), pin 1 of time base chip 1 (U4), and the emitter of transistor 2 (Q2) are grounded.

7. A resistance, inductance and capacitance measurement circuit based on STM32 according to claim 1, characterized in that: The capacitance measurement module (5) includes a time base chip, a resistor, a capacitor, a sliding rheostat, and a terminal. The signal interface of the capacitance measurement module (5) is connected to pin 3 of the time base chip 2 (U5), pin 5 of the time base chip 2 (U5) is connected to one end of capacitor 8 (C8), pin 6 of the time base chip 2 (U5) is divided into three paths and respectively connected to pin 2 of the time base chip 2 (U5), one end of resistor 15 (R15), and pin 2 of terminal 4 (P3), and the other end of resistor 15 (R15) is connected to the first pin of the time base chip 2 (U5), the second pin of the time base chip 2 (U5), ...P3), and the second pin of the time base chip 2 (U5). After resistor fourteen (R14) is connected in series, it is connected to the sliding end of sliding rheostat four (RP4). Pin 7 of time base chip two (U5) is divided into two paths and connected to one end of resistor eleven (R11) and one end of sliding rheostat four (RP4) respectively. The other end of resistor eleven (R11) is divided into three paths and connected to the VCC power supply, pins 4 and 8 of time base chip two (U5) respectively. The other end of capacitor eight (C8), pin 1 of time base chip two (U5) and pin 1 of terminal four (P3) are grounded.

8. A resistance, inductance and capacitance measurement circuit based on STM32 according to claim 5, 6 or 7, characterized in that: The models of time base chip 1 (U4), time base chip 2 (U5), and time base chip 3 (U6) are NE555.

Images