CN208367071U - Multifunctional digital universal meter - Google Patents
Multifunctional digital universal meter Download PDFInfo
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- CN208367071U CN208367071U CN201820745020.5U CN201820745020U CN208367071U CN 208367071 U CN208367071 U CN 208367071U CN 201820745020 U CN201820745020 U CN 201820745020U CN 208367071 U CN208367071 U CN 208367071U
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Abstract
The utility model discloses a kind of Multifunctional digital universal meters, comprising: microprocessor, including single-chip computer and its peripheral circuit；Display, for showing the test result of tested component, the signal output end of single-chip microcontroller connects display；555 test modules, 555 test module and 555 tested chips connect and compose multivibrator, and its output end connection single-chip microcontroller is I/O mouthfuls corresponding；It is I/O mouthfuls corresponding that 741 test modules, tested 741 integrated package of amplifier of 741 test module connection, and its input, output end are separately connected single-chip microcontroller；Regulator block test module, the regulator block test module and tested regulator block connect and compose regulator block capacitor filter, and its output end is I/O mouthfuls corresponding by AD converter connection single-chip microcontroller.The utility model compensates for limitation existing for the digital multimeter measurement device type of the prior art, and has the characteristics that simple circuit, arithmetic speed are fast, measurement accuracy is high, at low cost as main control chip using single-chip microcontroller.
Description
Technical field
The utility model relates to instrument fields, more particularly to a kind of Multifunctional digital universal meter.
Background technique
The quality problems that product is improved with the rapid development of electronic information industry, in row, to electronic component
Quality requirements are also higher and higher, to guarantee that entire electronic system can run well, usually first to measure the matter of electronic component
Measure state status.Currently, the type of the digital multimeter of the prior art is very more, it is widely used in measurement resistance, voltage, electric current etc.
Parameter, but the state of 555 chips, 741 integrated package of amplifier, integrated package of pressure-stabilizing can be tested without one kind, and this three
Application of the kind device blocks in usually subject experiment related with circuit is again very frequent.Therefore, for circuit staff
With the academic scientific research of lab assistant, the multi-functional number that at least can above-mentioned three kinds of device blocks be carried out with state verification is designed
Word multimeter is very necessary.
Utility model content
The utility model provides a kind of Multifunctional digital universal meter, and which overcome the digital multimeter of the prior art to be deposited
Shortcoming.
The technical scheme adopted by the utility model to solve the technical problem is as follows: a kind of Multifunctional digital universal meter, comprising:
Microprocessor, including single-chip computer and its peripheral circuit；
Display, for showing the test result of tested component, the signal output end of the single-chip microcontroller connects display；
555 test modules, for detecting the state quality of 555 chips, 555 test module and 555 tested chips connect
Composition multivibrator is connect, and its output end connection single-chip microcontroller is I/O mouthfuls corresponding；
741 test modules, for detecting the state quality of 741 integrated package of amplifier, the tested fortune of 741 test module connection
Put 741 integrated packages, and to be separately connected single-chip microcontroller I/O mouthfuls corresponding for its input, output end；
Regulator block test module, for detecting the state quality of regulator block, the regulator block test module and tested pressure stabilizing
Block connects and composes regulator block capacitor filter, and its output end is I/O mouthfuls corresponding by AD converter connection single-chip microcontroller.
It further, further include Test Diode module, whether for detecting diode current flow, the Test Diode module
Including resistance, one end of resistance connects power supply, and the other end connects the anode of measured diode, and the cathode of measured diode is grounded,
It is I/O mouthfuls corresponding that the anode of measured diode connects the single-chip microcontroller.
It further, further include triode test module, for the type of detection transistor, the triode test module packet
Resistance is included, one end of resistance connects power supply, and the other end connects the collector of tested triode, and the base stage for being tested triode connects institute
It states that single-chip microcontroller is I/O mouthfuls corresponding, is tested the emitter ground connection of triode.
It further, further include capacity measurement module, for detecting the size of capacitor, the capacity measurement module and tested
Capacitance connection constitutes 555 monostable circuits, and described corresponding external interrupt I/O mouthfuls of single-chip microcontroller of the connection of its output end.
It further, further include resistance test module, for the size of detection resistance, the resistance test module and tested
Resistance connects and composes 555 monostable circuits, and described corresponding external interrupt I/O mouthfuls of single-chip microcontroller of the connection of its output end.
It further, further include inductance measurement module, for testing the size of inductance, the inductance measurement module and tested electricity
Sense connects and composes bikini sine wave oscillation circuit, and described corresponding external interrupt I/O mouthfuls of single-chip microcontroller of the connection of its output end.
Further, 741 test module includes two diodes, the plus earth of one of diode, cathode
Connect the output end of tested 741 integrated package of amplifier；The anode of another diode connects the output of tested 741 integrated package of amplifier
End, cathode connect power supply；Reverse input end, noninverting input, the output end of tested 741 integrated package of amplifier are separately connected the list
Corresponding three I/O mouthfuls of piece machine, positive pole, the power cathode of tested 741 integrated package of amplifier are separately connected positive and negative power supply.
Further, the peripheral circuit includes reset circuit and crystal oscillating circuit, and the output of reset circuit connects the list
The RESET input of piece machine, crystal oscillating circuit connect the XTAL1 pin and XTAL2 pin of the single-chip microcontroller；The single-chip microcontroller is 51
Series monolithic.
Further, the single-chip microcontroller be 51 series monolithics, including model STC89C52, STC89C51,
Any single-chip microcontroller in AT89S51, AT89S52；The display includes the LCD MODULE of model LCD12864,
The RS pin of the LCD MODULE connects the AD0 pin of the single-chip microcontroller, described in the R/W pin connection of the LCD MODULE
The E pin of the AD1 pin of single-chip microcontroller, the LCD MODULE connects the AD2 pin of the single-chip microcontroller；LCD MODULE
GND pin, PSB pin, LED-B pin are grounded, and VCC pin and LED-A pin are all connected with power supply；The display also wraps
Adjustable resistance is included, which is connected between the GND pin of LCD MODULE and VCC pin, can be used to adjust display
Device brightness.
Further, further include key selecting module, the key selecting module include it is multiple with the test module one by one
Corresponding key switch, and its output end connection single-chip microcontroller is I/O mouthfuls corresponding, each key switch can be pressed respectively,
So that single-chip microcontroller responds test module corresponding with key switch.
Compared to the prior art, the utility model has the following beneficial effects:
1, can to 555 chips, amplifier 741 is integrated, state of regulator block is tested, compensate for the number of the prior art
Limitation existing for multimeter measurement device type, and microprocessor uses single-chip microcontroller (especially with 51 series monolithics)
As main control chip, have the characteristics that simple circuit, arithmetic speed are fast, measurement accuracy is high, at low cost.
2, the Test Diode module being further arranged/triode test module/capacity measurement module/resistance test mould
Block/inductance measurement module, further enriches the function of the digital multimeter of the utility model, makes the number ten thousand of the utility model
It is more complete with table function, the digital multimeter of the prior art can be replaced to test a variety of electronic components.Particularly,
The circuit structure of the Test Diode module/triode test module is very simple, directly with the corresponding port phase of single-chip microcontroller
Even, very intuitively, simply, fast.
3, the display preferably uses the LCD MODULE of model LCD12864, not only has LCD1602 liquid crystal
The all advantages of display module, moreover it is possible to Display of Chinese characters, so as to more intuitively show test result.
The utility model is described in further detail with reference to the accompanying drawings and embodiments；But one kind of the utility model is more
Function digit multimeter is not limited to the embodiment.
Detailed description of the invention
Fig. 1 is the circuit diagram of the microprocessor of the utility model；
Fig. 2 is the circuit diagram of the Test Diode module (containing measured diode) of the utility model；
Fig. 3 is the circuit diagram of the triode test module (containing tested triode) of the utility model；
Fig. 4 is the circuit diagram of the resistance test module (containing measured resistance) of the utility model；
Fig. 5 is the circuit diagram of the capacity measurement module (containing measured capacitance) of the utility model；
Fig. 6 is the circuit diagram of the inductance measurement module (containing tested inductance) of the utility model；
Fig. 7 is the circuit diagram of 555 test modules (containing tested 555 chips) of the utility model；
Fig. 8 is the circuit diagram of 741 test modules (containing tested 741 integrated package of amplifier) of the utility model；
Fig. 9 is the circuit diagram of the regulator block test module (by tested regulator block) of the utility model；
Figure 10 is the circuit diagram of the AD converter of the utility model；
Figure 11 is the circuit diagram of the display of the utility model；
Figure 12 is the circuit diagram of the key selecting module of the utility model；
Figure 13 is the principles of the present invention block diagram.
Specific embodiment
Embodiment, referring to Figure 1 shown in-Figure 13, a kind of Multifunctional digital universal meter of the utility model, comprising:
Microprocessor 20, including 51 series monolithics (referred to as 51 single-chip microcontrollers) U1 and its peripheral circuit；
Display 10, for showing the test result of tested component, the signal output end connection of the 51 single-chip microcontroller U1
Display；
555 test modules 90, for detecting the state quality of 555 chips, 555 test module 90 and 555 tested cores
Piece connects and composes multivibrator, and its output end connects I/O mouthfuls corresponding of external interrupt of 51 single-chip microcontroller U1 (such as INT0/
P3.2 pin)；
741 test modules 100, for detecting the state quality of 741 integrated package of amplifier, which connects quilt
741 integrated package of amplifier of survey, and two input terminal, an output end are separately connected corresponding three I/O of 51 single-chip microcontroller U1
Mouthful；
Regulator block test module 110, for detecting the state quality of regulator block (i.e. integrated package of pressure-stabilizing), regulator block tests mould
Block 110 and tested regulator block connect and compose regulator block typical capacitance filter circuit, and its output end is connected by AD converter
It is I/O mouthfuls corresponding to connect 51 single-chip microcontrollers.
In the present embodiment, the circuit structure of the microprocessor 20 as shown in Figure 1,51 single-chip microcontroller model
STC89C52, but not limited to this, for example, it is also possible to using 51 series such as model STC89C51, AT89S52, AT89S51
Single-chip microcontroller.The peripheral circuit includes reset circuit and crystal oscillating circuit, and the output of reset circuit connects the 51 single-chip microcontroller U1
The RESET input, crystal oscillating circuit connects the XTAL1 pin and XTAL2 pin of 51 single-chip microcontroller.Specifically, as shown in Figure 1,
The reset circuit includes resistance R1, resistance R2, capacitor C1 and key switch S0, and resistance R2 and key switch S0 connect, and with
Capacitor C1 is connected in parallel between power supply VCC and the RESET input of 51 single-chip microcontroller U1, the one end resistance R1 ground connection, and other end connection 51 is single
The RESET input of piece machine U1.The crystal oscillating circuit includes capacitor C2, capacitor C3, crystal oscillator Y1, and crystal oscillator Y1 connects
It connects between the XTAL2 pin and XTAL1 pin of 51 single-chip microcontrollers, the one end capacitor C2 connects the XTAL1 pin of 51 single-chip microcontroller U1, electricity
Hold the XTAL2 pin that the one end C3 connects 51 single-chip microcontroller U1, the capacitor C2 other end, the capacitor C3 other end and 51 single-chip microcontroller U1
GND pin is grounded, and the VCC pin and EA/VPP pin of 51 single-chip microcontroller U1 is all connected with power supply VCC.
In the present embodiment, the utility model further includes Test Diode module 40, whether for detecting diode current flow.Such as
Shown in Fig. 2, which includes resistance R3, and one end of resistance R3 connects power supply VCC, and other end connection is tested
The anode of diode Dx, the cathode ground connection of measured diode Dx, the anode of measured diode Dx connect the 51 single-chip microcontroller U1 phase
The I/O mouth answered, specifically can connect the P0.0 pin of 51 single-chip microcontroller U1.
In the present embodiment, the utility model further includes triode test module 50, the type for detection transistor.Such as figure
Shown in 3, which includes resistance R4, and one end of resistance R4 connects power supply VCC, other end connection tested three
The collector of pole pipe Tx, base stage connection 51 single-chip microcontroller for being tested triode Tx is I/O mouthfuls corresponding, is tested triode Tx's
Emitter ground connection.Specifically, the base stage for being tested triode Tx can connect the P0.1 pin of 51 single-chip microcontroller.
In the present embodiment, the utility model further includes resistance test module 60, and for the size of detection resistance, which is surveyed
Die trial block 60 and tested resistance Rx connect and compose 555 monostable circuits, and its output end connects the outside of 51 single-chip microcontroller
Interrupt I/O mouthfuls (such as INT0/P3.2 pin).Specifically, as shown in figure 4, resistance test module 60 includes 555 chip U2, resistance
R5, capacitor C4, capacitor C5, the one end resistance R5, the RST pin of 555 chip U2,555 chip U2 VCC pin be all connected with power supply
VCC, the resistance R5 other end connect the DIS pin of 555 chip U2；The one end measured resistance Rx connects the DIS pin of 555 chip U2,
The measured resistance Rx other end, the one end capacitor C5 are all connected with the THR pin of 555 chip U2, THR pin, the TRIG of 555 chip U2
Pin links together；The CVOLT pin of 555 chip U2 of the one end capacitor C4 connection, the capacitor C4 other end, the capacitor C5 other end,
And 555 the GND pin of chip U2 be grounded.
In the present embodiment, the utility model further includes capacity measurement module 70, for detecting the size of capacitor.The capacitor is surveyed
Die trial block 70 and tested capacitor Cx connect and compose 555 monostable circuits, and its output end OUT connection 51 single-chip microcontroller U1
I/O mouthfuls of external interrupt (such as INT0/P3.2 pin).Specifically, as shown in figure 5, capacity measurement module 70 includes 555 chips
U3, resistance R6, resistance R7, capacitor C6 and capacitor Cx, the one end resistance R1, the RST pin of 555 chip U3,555 chip U3
VCC pin is all connected with power supply VCC, and the resistance R6 other end connects the DIS pin of 555 chip U3；The one end resistance R7 connects 555 chips
The DIS pin of U3, the resistance R7 other end, the one end capacitor C6 are all connected with the THR pin of 555 chip U3, the THR pipe of 555 chip U3
Foot, TRIG pin link together；The one end measured capacitance Cx connects the CVOLT pin of 555 chip U2, and measured capacitance Cx is another
The GND pin at end, the capacitor C6 other end and 555 chip U3 is grounded.
In the present embodiment, the utility model further includes inductance measurement module 80, for testing the size of inductance, the electrical sensing
Die trial block 80 and tested inductance Lx connect and compose bikini sine wave oscillation circuit, and 51 single-chip microcontroller U1's described in its output end is outer
Interrupt I/O mouthfuls (such as INT0/P3.2 pin) in portion.Specifically, as shown in fig. 6, inductance measurement module 80 includes resistance R8, resistance
R9, resistance R10, resistance R11, resistance R12, capacitor C7, capacitor C8, capacitor C9, capacitor C10, capacitor C11, triode T1, three poles
Pipe T2.The one end resistance R8, the one end capacitor C10, the one end capacitor C11 connecting triode T1 base stage, the one end resistance R9 is grounded, electricity
It is in parallel with capacitor C11 to hold C10；The resistance R8 other end connects the one end capacitor C7, the transmitting of capacitor C7 other end connecting triode T1
Pole, the one end capacitor C9 and the one end capacitor C8, the emitter and the resistance R9 other end of capacitor C8 other end connecting triode T1；Three poles
The collector of pipe T1 is by being tested inductance Lx connection power supply VCC；The base stage of capacitor C9 other end connecting triode T2, triode
The collector of T2 is grounded by the emitter of resistance R12 connection power supply VCC, triode T2 by resistance R10；Resistance R11 connection
Between power supply VCC and the base stage of triode T2.It, can also be in the output end OUT elder generation of bikini sine wave oscillation circuit except this
Add level-one single tube to amplify, then sine wave is converted to square wave with comparator, then square wave output port is connected to 51 single-chip microcontroller U1
I/O mouthfuls of external interrupt, processing is amplified to signal with this.
In the present embodiment, as shown in fig. 7,555 test modules 90 specifically include resistance R13, resistance R14, capacitor C12, electricity
Hold C13, the one end resistance R13, the RST pin of 555 tested chip U4,555 tested chip U4 VCC pin be all connected with power supply
VCC, resistance the R13 other end, the one end resistance R14 are all connected with the DIS pin of 555 tested chip U4；The resistance R14 other end, electricity
Hold the THR pin that the one end C13 is all connected with 555 tested chip U4, THR pin, the TRIG pin of 555 tested chip U4 connects
It is connected together；The CVOLT pin of 555 tested chip U4 of the one end capacitor C12 connection, it is capacitor C12, C13 other end, tested
The GND pin of 555 chip U4 is grounded；The OUT pin of 555 tested chip U4 connects the external interrupt of 51 single-chip microcontroller
I/O mouthfuls (such as INT0/P3.2 pin).
In the present embodiment, as shown in figure 8,741 test module 100 includes two diodes D1, D2, one of them two
The plus earth of pole pipe D1, cathode connect the 6 pin output ends of tested 741 integrated package U5 of amplifier；Another diode D2 is just
Pole connects the 6 pin output ends of tested 741 integrated package U5 of amplifier, and cathode connects power supply VCC；Tested 741 integrated package U5's of amplifier
Reverse input end, noninverting input, output end are separately connected wherein three I/O mouthfuls of the 51 single-chip microcontroller U1, this three specific
The I/O mouthfuls of P3.5 pins, P3.6 pin and P3.7 pin that can be 51 single-chip microcontroller U1 respectively.7 pipes of tested 741 integrated package of amplifier
Foot, 4 pins are separately connected 12V power supply, -12V power supply.
In the present embodiment, as shown in figure 9, the regulator block test module 110 includes input capacitance C14, output capacitance
C15.1 pin of tested regulator block U6 represents ground terminal, and 2 pins represent voltage input end, and 3 pins represent voltage output end, electricity
The one end for holding C14 is connected with input voltage with the input terminal of regulator block U6, one end, output voltage and the regulator block U6 of capacitor C15
Output end connection, the ground terminal of input capacitance C14, one end of output capacitance C15 and regulator block U6 is grounded, and output voltage connects
The input terminal of AD converter.The circuit of AD converter is as shown in Figure 10, which includes the integrated of model ADC0804
Chip U7, resistance R15, resistance R16, resistance R17, resistance R18, capacitor C16, the one end resistance R16 constitute the input of AD converter
End, the resistance R16 other end connect integrated chip U7 the 6th pin, the one end resistance R17, integrated chip U7 the 20th pin connect
Power supply VCC is met, the other end connects one end of the 9th pin and resistance R18 of integrated chip U7, the resistance R18 other end and integrated core
The 10th pin of piece U7 is grounded；Capacitor C16 is connected between the 4th pin of integrated chip U7 and the 7th pin, integrated chip U7
The 7th pin, the 8th pin is grounded；Resistance R15 is connected between the 4th pin of integrated chip U7 and the 19th pin；It is integrated
It is I/O mouthfuls corresponding that the 18th pin of 11- of chip U7 is separately connected 51 single-chip microcontroller U1.
In the present embodiment, as shown in figure 11, the display includes the LCD MODULE U8 of model LCD12864, should
The RS pin of LCD MODULE U8 connects the AD0 pin of the 51 single-chip microcontroller U1, the R/W pin of LCD MODULE U8
The AD1 pin of the 51 single-chip microcontroller U1 is connected, the E pin of LCD MODULE U8 connects the AD2 pipe of the 51 single-chip microcontroller U1
Foot；GND pin, PSB pin, the LED-B pin of LCD MODULE U8 is grounded, and VCC pin and LED-A pin are all connected with
Power supply VCC；The display further includes adjustable resistance R19, and adjustable resistance R19 is connected to the GND pipe of LCD MODULE U8
Between foot and VCC pin.
In the present embodiment, the utility model further includes key selecting module 30, and as shown in Figure 12,13, which selects mould
Block 30 includes 8 key switch S1-S8, and there are 8 output end K1-K8,8 output end K1-K8 to be separately connected described 51
Single-chip microcontroller U1 is I/O mouthfuls corresponding.Above-mentioned 8 kinds of test modules of 8 key switches and the utility model correspond, and each press
Key switch can be pressed (only a key switch is allowed to be pressed every time) respectively, so that single-chip microcontroller response is corresponding with key switch
Test module.The utility model shares 8 kinds of test functions: being able to detect the quality and positive and negative anodes, transistor of diode
Type, the resistance value of resistance, the size of the capacity of capacitor, inductance, and to 555 chips, 741 integrated package of amplifier, regulator block matter
Fine or not state is measured to be tested.When test, tested component is accessed into corresponding test module, and press corresponding key
Switch responds 51 single-chip microcontroller U1 only to the current tested corresponding test module of component, is tested component and its at this time
Corresponding test module constitutes a functional circuit, and 51 single-chip microcontrollers utilize it by obtaining the output signal of the functional circuit
Signal carry out it is relevant be calculated testing result, or with quality that device is investigated whether being consistent under normal circumstances, and aobvious
Show the liquid crystal screen display measurement result of device.For example, wanting test diode, then diode is accessed in Test Diode module,
And key switch corresponding with the Test Diode module is pressed, 51 single-chip microcontrollers can be obtained the output of the Test Diode module
Signal carries out relevant processing using its signal and obtains testing result, and controls display and show corresponding measurement result.Remaining
The test operation of 7 kinds of tested components (triode, resistance, capacitor, inductance, 555 chips, 741 integrated package of amplifier, regulator block)
It is identical as the test operation of diode.Before no any key switch is pressed, the display screen of display show " please select:
Test component.".The key switch can be used other types of switch (such as toggle switch etc.) and replace, key switch
Belong to equivalent replacement with other types of switch.
The utility model is as follows to the test philosophy of above 8 kinds of tested components:
1) whether test diode is connected: measured diode Dx is accessed as shown in Figure 2 in Test Diode module, according to
The difference for the signal that 51 single-chip microcontrollers are read from the pin specifically judges whether to be connected, and detects low electricity for P0.0 mouthfuls when 51 single-chip microcontroller
Usually, illustrate that measured diode Dx is connected, the display screen of display shows " P " character；When 51 single-chip microcontrollers detect high level,
Illustrate that measured diode is in nonconducting state, display is without display.
2) it tests triode-type: tested triode Tx is accessed as shown in Figure 3 in triode test module, triode
What type test utilized is triode classics connection circuit, one of I/O (specifically P0.1 pin) of 51 single-chip microcontrollers and by
The base stage for surveying triode Tx is connected, and tested triode Tx collector is attached by resistance R4 and power supply VCC, and emitter connects
Ground specifically judges the type of triode according to the difference for the signal that 51 single-chip microcontrollers are read from the pin, and if tested triode Tx
For NPN type, then the display screen of display shows " NPN " character, if tested triode Tx is positive-negative-positive, the display screen of display
Show " PNP " character.
Test result is as follows for diode, triode shown in table:
Diode and triode test result
3) resistance sizes are tested, by measured resistance by Fig. 4 access resistance test module.Test for resistance utilizes
The monostable experimental program of 555 timers classics.When test, the OUT pin of 555 chip U2 generates rectangular wave pulse, and its is defeated
Outlet OUT pin connects I/O mouthfuls of external interrupt (INT0/P3.2) of 51 single-chip microcontroller U1, and 51 pulse waves are counted
While carry out timing, tested electricity can be obtained by accordingly calculating to obtaining output frequency f, and being calculated by the following formula
Hinder RxResistance value, and the display screen of display shows the resistance value of measured resistance.
By
?
Several resistance are tested respectively using the MY65 type digital multimeter of the utility model and the prior art, are tested
As a result as shown in the table:
Resistance test result
As seen from the above table, the utility model is higher to the measuring accuracy of resistance sizes, and test error is small, and test result is more smart
It is quasi-.
4) capacitance size is tested: by measured capacitance Cx by Fig. 5 access capacity measurement module.Test for capacitor, together
Sample can use the more classical monostable experimental program of 555 timers.When test, the OUT pin of 555 chip U3 generates rectangle
Impulse wave, and its output end OUT pin connects I/O mouthfuls of external interrupt (INT0/P3.2) of 51 single-chip microcontroller U1,51 single-chip microcontrollers pair
Timing is carried out while impulse wave is counted, and by output frequency f is accordingly calculated, and is calculated by the following formula
The capacitance size of measured capacitance Cx is obtained, and the display screen of display shows the capacitance size of measured capacitance.
By
If R6=R7, obtain
Several capacitors are tested respectively using the MY65 type digital multimeter of the utility model and the prior art, are tested
As a result as shown in the table:
Capacity measurement result
As seen from the above table, the utility model is higher to the measuring accuracy of capacitance size, and test error is small, and test result is more smart
It is quasi-.
5) inductance size is tested: by tested inductance Lx by Fig. 6 access inductance measurement module.For inductance measurement, 3 points
Formula sine-wave oscillation scheme, shaking principle according to capacitance three-point type sine wave has following formula (5).
By
?
When testing inductance, the display screen of display shows the size of tested inductance.
Several capacitors are tested respectively using the MY65 type digital multimeter of the utility model and the prior art, are tested
As a result as shown in the table:
Inductance measurement result
As seen from the above table, the utility model is higher to the measuring accuracy of inductance size, and test error is small, and test result is more smart
It is quasi-.
6) 555 chip status are tested: 555 tested chip U4 are accessed in 555 test modules by Fig. 7.For 555 cores
The test of piece, using traditional multivibrator scheme, it is only necessary to using 51 monolithic machine testing its output end whether be square wave i.e.
Can, if square wave, it was demonstrated that 555 chip status are normally that otherwise 555 chips are exactly bad, and display shows that " 555 survey
Examination.Situation: bad ".
7) tested 741 integrated package U5 of amplifier 741 integrated package state verification of amplifier: is accessed into 741 test modules by Fig. 8
In.Test to 741 integrated package of amplifier, using the 741 integrated package comparator classics circuit connection scheme of amplifier of insertion, benefit
With the output signal of the output port of the 51 monolithic machine testing comparators it may determine that the quality situation of amplifier, if by
The 2 pin inverting input terminal voltages of the 741 integrated package U5 of amplifier of survey are greater than 3 pin normal phase input end voltages, then 51 monolithic machine examination
Measuring voltage is 0, so 51 single-chip microcontrollers can judge that tested 741 integrated package U5 of amplifier is by detecting output voltage
, display shows " 741 tests.Situation: normal ".If the 2 pin inverting input terminals of tested 741 integrated package U5 of amplifier
For voltage less than 3 pin normal phase input end voltages, 51 single-chip microcontrollers detect that voltage is or 0,51 single-chip microcontrollers pass through detection output electricity
Pressure can judge that tested 741 integrated package U5 of amplifier is bad.
555 chips and amplifier 741 detect integrated package, and test result is as follows shown in table:
555 and 741 test result of amplifier
8) tested regulator block regulator block state verification: is accessed into regulator block test module by Fig. 9.When measurement, in circuit
Voltage is added at input voltage, AD converter will be connect at output voltage, AD converter converts analog signals into digital signal,
Data transmission is handled to single-chip microcontroller, calculates corresponding voltage value, is then compared with standard regulator block voltage value, in turn
Learn the quality of regulator block quality state.Finally, carrying out corresponding liquid crystal display by 51 single-chip microcontrollers control display.If measuring steady
Briquetting output end voltage is stable and in effective theory value, then illustrates that the regulator block is functional, otherwise illustrate the regulator block
It is bad.
It is as shown in the table using test structure of the utility model to 7805 regulator blocks, LM11117 regulator block:
Regulator block test result
A kind of Multifunctional digital universal meter of the utility model, has the advantage that and compensates for existing digital multimeter
Limitation existing for measurement device type facilitates circuit designer, lab assistant to test a variety of common devices；More
The shortcomings that having mended existing general instrument fills measurement blind area, especially especially sensitive to small resistance, small capacitances, small inductor, essence
It is close；When detecting the basic parameter of diode, triode using 51 one-chip machine ports, directly it is connected with the port of 51 single-chip microcontrollers, directly
It sees, is simple, is quick；The parameter measurement of a variety of circuit components is completed in a mini system, it is intelligent and accurate, it is sufficient to meet
Circuit designer high-precision requirement is the improvement direction of later electronic measuring instrument；Using LCD12864 LCD MODULE,
Not only with all advantages of 1602 liquid crystal, and energy Display of Chinese characters on the basis of 1602, the data of more intuitive display test；
System performance safety, stablizes, and measurement accuracy is high, and it is convenient to operate, practical.
Above-described embodiment only is used to further illustrate a kind of Multifunctional digital universal meter of the utility model, but this is practical new
Type is not limited to embodiment, made by the above technical examples according to the technical essence of the present invention any simply to repair
Change, equivalent variations and modification, each falls in the protection scope of technical solutions of the utility model.
Claims (10)
1. Multifunctional digital universal meter, it is characterised in that: include:
Microprocessor, including single-chip computer and its peripheral circuit；
Display, for showing the test result of tested component, the signal output end of the single-chip microcontroller connects display；
555 test modules, for detecting the state quality of 555 chips, which connect structure with 555 tested chips
At multivibrator, and its output end connection single-chip microcontroller is I/O mouthfuls corresponding；
741 test modules, for detecting the state quality of 741 integrated package of amplifier, the tested amplifier of 741 test module connection
741 integrated packages, and to be separately connected single-chip microcontroller I/O mouthfuls corresponding for its input, output end；
Regulator block test module, for detecting the state quality of regulator block, regulator block test module is connect with tested regulator block
Regulator block capacitor filter is constituted, and its output end is I/O mouthfuls corresponding by AD converter connection single-chip microcontroller.
2. Multifunctional digital universal meter according to claim 1, it is characterised in that: further include Test Diode module, use
Whether detecting diode current flow, which includes resistance, and one end of resistance connects power supply, and the other end connects quilt
The anode of diode, the cathode ground connection of measured diode are surveyed, the anode of measured diode connects the corresponding I/O of single-chip microcontroller
Mouthful.
3. Multifunctional digital universal meter according to claim 1, it is characterised in that: further include triode test module, use
In the type of detection transistor, which includes resistance, and one end of resistance connects power supply, and other end connection is tested
The collector of triode, the base stage connection single-chip microcontroller for being tested triode is I/O mouthfuls corresponding, and the emitter of tested triode connects
Ground.
4. Multifunctional digital universal meter according to claim 1, it is characterised in that: further include resistance test module, be used for
The size of detection resistance, the resistance test module and tested resistance connect and compose 555 monostable circuits, and its output end connects
Corresponding external interrupt I/O mouthfuls of the single-chip microcontroller.
5. Multifunctional digital universal meter according to claim 1, it is characterised in that: further include capacity measurement module, be used for
The size of capacitor is detected, the capacity measurement module and tested capacitance connection constitute 555 monostable circuits, and its output end connects
Corresponding external interrupt I/O mouthfuls of the single-chip microcontroller.
6. Multifunctional digital universal meter according to claim 1, it is characterised in that: further include inductance measurement module, be used for
The size of inductance is tested, the inductance measurement module and tested inductance connection constitute bikini sine wave oscillation circuit, and it is exported
Described corresponding external interrupt I/O mouthfuls of single-chip microcontroller of end connection.
7. Multifunctional digital universal meter according to claim 1, it is characterised in that: 741 test module includes two
Diode, the plus earth of one of diode, cathode connect the output end of tested 741 integrated package of amplifier；Another two pole
The anode of pipe connects the output end of tested 741 integrated package of amplifier, and cathode connects power supply；It is tested the reversed defeated of 741 integrated package of amplifier
Enter end, noninverting input, output end are separately connected corresponding three I/O mouthfuls of the single-chip microcontroller, be tested the electricity of 741 integrated package of amplifier
Source anode, power cathode are separately connected positive and negative power supply.
8. Multifunctional digital universal meter according to claim 1, it is characterised in that: the peripheral circuit includes reset circuit
And crystal oscillating circuit, the output of reset circuit connect the RESET input of the single-chip microcontroller, crystal oscillating circuit connects the single-chip microcontroller
XTAL1 pin and XTAL2 pin；The single-chip microcontroller is 51 series monolithics.
9. Multifunctional digital universal meter according to claim 1, it is characterised in that: the single-chip microcontroller is 51 serial monolithics
Machine, including any single-chip microcontroller in model STC89C52, STC89C51, AT89S51, AT89S52；The display includes
The RS pin of the LCD MODULE of model LCD12864, the LCD MODULE connects the AD0 pin of the single-chip microcontroller, should
The R/W pin of LCD MODULE connects the AD1 pin of the single-chip microcontroller, and the E pin of the LCD MODULE connects the list
The AD2 pin of piece machine；GND pin, PSB pin, the LED-B pin of LCD MODULE are grounded, VCC pin and LED-A pipe
Foot is all connected with power supply；The display further includes adjustable resistance, the adjustable resistance be connected to LCD MODULE GND pin and
Between VCC pin.
10. Multifunctional digital universal meter according to claim 1 to 6, it is characterised in that: further include key choosing
Module is selected, which includes multiple and the one-to-one key switch of the test module, and its output end connects
The single-chip microcontroller is I/O mouthfuls corresponding, and each key switch can be pressed respectively, so that single-chip microcontroller response is corresponding with key switch
Test module.
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|---|---|---|---|
| CN201820745020.5U CN208367071U (en) | 2018-05-18 | 2018-05-18 | Multifunctional digital universal meter |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201820745020.5U CN208367071U (en) | 2018-05-18 | 2018-05-18 | Multifunctional digital universal meter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110763908A (en) * | 2019-11-11 | 2020-02-07 | 绵阳市维博电子有限责任公司 | Digital display DC meter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110763908A (en) * | 2019-11-11 | 2020-02-07 | 绵阳市维博电子有限责任公司 | Digital display DC meter |
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