CN203894328U

CN203894328U - Digital RLC tester

Info

Publication number: CN203894328U
Application number: CN201420322474.3U
Authority: CN
Inventors: 张新安
Original assignee: Hunan University of Science and Engineering
Current assignee: Hunan University of Science and Engineering
Priority date: 2014-06-18
Filing date: 2014-06-18
Publication date: 2014-10-22
Anticipated expiration: 2024-06-18

Abstract

The utility model relates to a digital RLC tester comprising a resistor-inductor-capacitor frequency conversion circuit, an AT89S51 single-chip microcomputer circuit, an LED display circuit and a power supply circuit. The connection relation of all components is shown in the drawing. According to a multi-vibrator circuit based on the design of the CB555 integrated circuit, measurement of the resistor, inductor, and capacitor is converted into measurement of a frequency of a square signal outputted by the CB555 integrated circuit. The AT89S51 single-chip microcomputer is used for carrying out data acquisition and processing and a four-digit LED nixie tube is driven to display the measurement value of the tested resistor, inductor or capacitor. And a 78L05 three-end fixed integrated voltage stabilizer is used for power supplying. Besides, the resistance measurement range is from 0 to 20 milliohms; the inductance measurement range is from 0 to 20 henries; and the capacitance measurement range is from 0 to 2000 microfarads. The tester has the following active effects: the measurement precision is high; the speed is fast; the size is small; the function is powerful; the power consumption is low; the range is wide; the number reading is convenient; and the price is low.

Description

A kind of digital RLC tester

Technical field

The utility model relates to electronic measuring instrument technical field, is specifically related to a kind of digital RLC tester.

Background technology

In design, production, inspection and the maintenance of electronic product, often need measuring resistance, inductance and electric capacity, the develop rapidly of electronic technology, makes RLC tester become a kind of conventional electronic measuring instrument.The measuring method of traditional resistance, inductance and electric capacity has three kinds of voltammetry, bridge method and resonance methods.Voltammetry measuring process is many, has intrinsic method error; Bridge measurement precision is high, but speed is slow; Resonance method measurement circuit is simple, and speed is fast, but precision is low.The development of digital circuit and integrated circuit technique, for the digitized measurement of resistance, inductance and electric capacity provides good condition.The digital RLC tester of making of single-chip microcomputer, has that measuring speed is fast, precision is high and the advantage such as convenient reading, the measurement of resistance, inductance and electric capacity can apply to widely the design, production, inspection of electronic product and maintenance time.

Summary of the invention

For solving the deficiency of existing RLC tester, the utility model discloses a kind of digital RLC tester.This numeral RLC tester adopts the multi-resonant oscillating circuit of CB555 integrated circuit (IC) design, the measurement of resistance, inductance and electric capacity is converted to the measurement of the square-wave signal frequency to the output of CB555 integrated circuit, utilize AT89S51 single-chip microcomputer to carry out data acquisition and processing (DAP), and drive four LED charactrons to show the measured value of measured resistance, inductance or electric capacity, select the fixing integrated regulator power supply of 78,L05 tri-ends, the measurement range of resistance is 0～20M Ω, the measurement range of inductance is 0～20H, and the measurement range of electric capacity is 0～2000 μ F.

For achieving the above object, the utility model adopts following technical scheme: the utility model is made up of resistance inductance capacitance freq converting circuit, AT89S51 single chip circuit, LED display circuit and power circuit.7 pin connection function switch K1-1 of the CB555 integrated circuit of resistance inductance capacitance freq converting circuit, 2,6 pin connection function switch K1-2,3 pin connect the P3.2 end of AT89S51 single-chip microcomputer.The stroke that P1.0～P1.6 end of AT89S51 single-chip microcomputer connects respectively LED display circuit drives a～g end, the dp end of P1.7 termination LED display circuit, R3, R4, R5, R6 position that P0.0, P0.1, P0.2, P0.3 end connect respectively LED display circuit drive input end, and P0.4, P0.5, P 0.6 end be R end, L end and the C end of the function switch K1-1 of connecting resistance inductance capacitance freq converting circuit respectively.The input termination electric main of power circuit, the power input of output terminal connecting resistance inductance capacitance freq converting circuit, AT89S51 single chip circuit and LED display circuit.The measurement range of resistance is 0～20M Ω, and the measurement range of inductance is 0～20H, and the measurement range of electric capacity is 0～2000 μ F.

Good effect of the present utility model is: measuring accuracy is high, speed is fast, volume is little, function is strong, low in energy consumption, broad quantum, convenient reading, low price.

Brief description of the drawings

Fig. 1 is block diagram of the present utility model.

Fig. 2 is circuit theory diagrams of the present utility model.

Embodiment

As shown in Figure 1, the utility model is made up of resistance inductance capacitance freq converting circuit, AT89S51 single chip circuit, LED display circuit and power circuit.7 pin connection function switch K1-1 of the CB555 integrated circuit of resistance inductance capacitance freq converting circuit, 2,6 pin connection function switch K1-2,3 pin connect the P3.2 end of AT89S51 single-chip microcomputer.The stroke that P1.0～P1.6 end of AT89S51 single-chip microcomputer connects respectively LED display circuit drives a～g end, the dp end of P1.7 termination LED display circuit, R3, R4, R5, R6 position that P0.0, P0.1, P0.2, P0.3 end connect respectively LED display circuit drive input end, and P0.4, P0.5, P 0.6 end be R end, L end and the C end of the function switch K1-1 of connecting resistance inductance capacitance freq converting circuit respectively.The input termination electric main of power circuit, the power input of output terminal connecting resistance inductance capacitance freq converting circuit, AT89S51 single chip circuit and LED display circuit.

As shown in Figure 2.

Resistance inductance capacitance freq converting circuit is by CB555 integrated circuit in the time of measuring resistance, capacitor C 1, C2, resistance R _r, function switch K1, range selector K2 and measured resistance R xthe multi-resonant oscillating circuit of composition.Its oscillation frequency f _r=1.449/ (R _r+ 2R x) C1, .As C1 and R _rone timing, is converted to the square-wave signal frequency to the 3 pin outputs of CB555 integrated circuit by the measurement of resistance f _rmeasurement.Through single-chip microcomputer collection f _rbe converted into R x, and driving LED display circuit can show R xmeasured value.

Resistance inductance capacitance freq converting circuit is by CB555 integrated circuit in the time of inductance measuring, capacitor C 2, resistance R _l, diode D1, function switch K1, range selector K2 and tested inductance L xthe multi-resonant oscillating circuit of composition.Its oscillation frequency f _l=0.345R _l/ L xl x=0.345R _l/ f _l.Work as R _lone timing, is converted to the square-wave signal frequency to the 3 pin outputs of CB555 integrated circuit by the measurement of inductance f _lmeasurement.Through single-chip microcomputer collection f _lbe converted into L x, and driving LED display circuit can show L xmeasured value.

Resistance inductance capacitance freq converting circuit is by CB555 integrated circuit in the time measuring electric capacity, capacitor C 2, resistance R _c, R ₁, function switch K1, range selector K2 and measured capacitance C xthe multi-resonant oscillating circuit of composition.Its oscillation frequency f _c=1.449/ (R _c+ 2R1) C x, C x=1.449/ (R _c+ 2R1) f _c.Work as R _cwith R1 mono-timing, the measurement of electric capacity is converted to the square-wave signal frequency to the 3 pin outputs of CB555 integrated circuit f _cmeasurement.Through single-chip microcomputer collection f _cbe converted into C x, and driving LED display circuit can show C xmeasured value.

Function switch K1 is DPTT double-pole triple throw switch, for the function conversion of measuring resistance, inductance or electric capacity, K2 is hilted broadsword nine throw switches, for range conversion, three ranges of measuring resistance design are: 0～2000 Ω, 0～2000K Ω, 0～20M Ω, three ranges of inductance measuring design are: 0～2000 μ H, 0～2000mH, 0～20H, three ranges measuring capacitor design are: 0～2000pF, 0～2000nF, 0～2000 μ F.

AT89S51 single chip circuit is by AT89S51 single-chip microcomputer, resistance R 2, and capacitor C 3, C4, C5, crystal oscillator X1 and button switch K 3 form.AT89S51 is a low-power consumption, 8 single-chip microcomputers of high-performance CMOS, 40 pins, including 4KB can overprogram Flash storer and 128 × 8 SRAM, 32 two-way I/O mouths in outside, 2 16 programmer timing counters, 2 full duplex serial communication ports, watchdog circuit, on-chip clock oscillator.

9 pin of AT89S51 are reset terminals, and high level resets.The reset circuit of R2, C5 and K3 composition single-chip microcomputer.While switching on power, 5V power supply charges to C5, and because the voltage at C5 two ends can not suddenly change, 9 pin are high level, monolithic processor resetting, the voltage at C5 two ends increases gradually simultaneously, in the time that the voltage at C5 two ends increases to 5V, charging finishes, and resetting pin voltage is 0V, and single-chip microcomputer enters normal operating conditions.Button switch K 3 is hand-reset buttons, and while pressing K3,9 pin are high level, and single-chip microcomputer enters reset mode, and while unclamping K3,9 pin are low level, and single-chip microcomputer exits reset mode.18 pin of AT89S51,19 pin internal circuits and outside crystal oscillator X1, capacitor C 3, C4 form clock oscillation circuit, and C3, C4 are trimmer.P3.2 is input end, joins with CB555 ic output 3 pin.P0.4, P0.5 and P0.6 are for the identification of function of measuring resistance, inductance or electric capacity.

LED display circuit is made up of charactron DS1～DS4, resistance R 3～R10 and triode Q1～Q4.DS1～DS4 adopts common cathode LED charactron, every section route selection parallel connection, and R3～R10 is current-limiting resistance, Q1～Q4 is that position drives a triode.Adopt dynamic scan display mode, with software to graphemic code decoding.P1.0～P1.6 end of single-chip microcomputer is for the output of digital seven sections of stroke graphemic codes that show, P1.7 end is for the output of the digital radix point showing, P0.0, P0.1, P0.2, P0.3 end drive code output for the dynamic scan position of four charactrons.AT89S51 single-chip microcomputer is the position code selection of the section of sending code selection and corresponding position LED charactron successively, and the dynamic scan of realizing measured resistance, inductance or capacitor measured value shows.

Power circuit is by step-down transformer T1, commutation diode D2, D3, filter capacitor C6, C7, the fixing integrated regulator 78L05 composition of three ends.The AC rectification of 220V, filtering, voltage stabilizing can be obtained to 5V galvanic current and press, be digital RLC tester power supply.

The RLC tester of the utility model design, the measurement range of resistance is 0～20M Ω, the measurement range of inductance is 0～20H, the measurement range of electric capacity is 0～2000 μ F, each grade of error of resistance and capacitance measurement is all less than 0.5%, and each grade of error of inductance measurement is all less than 1%, and Overall Power Consumption is less than 3 W, high, the broad quantum of precision measured, speed is fast, volume is little, low in energy consumption, function strong, convenient reading, low price, has wide market outlook.

Claims

1. a digital RLC tester, is characterized in that: it is made up of resistance inductance capacitance freq converting circuit, AT89S51 single chip circuit, LED display circuit and power circuit; 7 pin connection function switch K1-1 of the CB555 integrated circuit of resistance inductance capacitance freq converting circuit, 2,6 pin connection function switch K1-2,3 pin connect the P3.2 end of AT89S51 single-chip microcomputer; The stroke that P1.0～P1.6 end of AT89S51 single-chip microcomputer connects respectively LED display circuit drives a～g end, the dp end of P1.7 termination LED display circuit, R3, R4, R5, R6 position that P0.0, P0.1, P0.2, P0.3 end connect respectively LED display circuit drive input end, and P0.4, P0.5, P 0.6 end be R end, L end and the C end of the function switch K1-1 of connecting resistance inductance capacitance freq converting circuit respectively; The input termination electric main of power circuit, the power input of output terminal connecting resistance inductance capacitance freq converting circuit, AT89S51 single chip circuit and LED display circuit; The measurement range of resistance is 0～20M Ω, and the measurement range of inductance is 0～20H, and the measurement range of electric capacity is 0～2000 μ F.

2. the digital RLC tester of one according to claim 1, is characterized in that: resistance inductance capacitance freq converting circuit is by CB555 integrated circuit in the time of measuring resistance, capacitor C 1, C2, resistance R _r, function switch K1, range selector K2 and measured resistance R xthe multi-resonant oscillating circuit of composition.

3. the digital RLC tester of one according to claim 1, is characterized in that: resistance inductance capacitance freq converting circuit is by CB555 integrated circuit in the time of inductance measuring, capacitor C 2, resistance R _l, diode D1, function switch K1, range selector K2 and tested inductance L xthe multi-resonant oscillating circuit of composition.

4. the digital RLC tester of one according to claim 1, is characterized in that: resistance inductance capacitance freq converting circuit is by CB555 integrated circuit in the time measuring electric capacity, capacitor C 2, resistance R _c, R ₁, function switch K1, range selector K2 and measured capacitance C xthe multi-resonant oscillating circuit of composition.

5. the digital RLC tester of one according to claim 1, is characterized in that: function switch K1 is DPTT double-pole triple throw switch, and for the function conversion of measuring resistance, inductance or electric capacity, K2 is hilted broadsword nine throw switches, changes for range.

6. the digital RLC tester of one according to claim 1, is characterized in that: AT89S51 single chip circuit is by AT89S51 single-chip microcomputer, resistance R 2, and capacitor C 3, C4, C5, crystal oscillator X1 and button switch K 3 form.

7. the digital RLC tester of one according to claim 1, it is characterized in that: LED display circuit is made up of charactron DS1～DS4, resistance R 3～R10 and triode Q1～Q4, DS1～DS4 adopts common cathode LED charactron, and every section route selection parallel connection, adopts dynamic scan display mode.

8. the digital RLC tester of one according to claim 1, is characterized in that: power circuit is by step-down transformer T1, commutation diode D2, D3, filter capacitor C6, C7, the fixing integrated regulator 78L05 composition of three ends.