The digital voltage meter refers to a voltage meter that is changed from the pointer to a number, i.e., a digital tube display or a liquid crystal panel display. There are also many classification methods. If you have a bit number, such as 3/2, 5, 8 bits; with measurement speed, such as high speed, low speed; with volume, weight, such as pocket, portable, Desktop. However, it is usually divided into two major categories in different A / D conversion methods. One type is a direct conversion type, also known as a comparison; the other is indirect conversion type, also known as the integral, including voltage-time transformation (VT Transform) and voltage-frequency transform (VF transformation).
(1) Successive approximation compariscies The comparative voltage meter is compared by comparing the measured voltage to the continuously decreasing reference voltage, and then the display is displayed. Although a certain time is required for a certain time, it is necessary to complete a number of pieces of shooting, but as long as the speed of the beat is accelerated, it can still be measured at an instant.
(2) Voltage-Time Transform Syringe The voltage-time transform type means that the measurement is converted to the time interval Δt, the larger the voltage, the larger the ΔT, and then press the ΔT size control timing pulse. Its count value is a voltage value. Voltage-Time Transform type is also known as a V-T type or ramp voltage.
(3) Voltage-frequency transform type so-called voltage-frequency transform type means that the measurement is converted to a frequency value, and then the frequency value is displayed in the frequency table, that is, the size of the voltage value can be reflected, which is also known For V-F.
1,51 single-chip simple digital voltmeter
Instructions for use:
1. Can set the voltage alarm value upper limit, press the "Set" button to press the "↑" button and "↓" button to modify the voltage alarm value upside down, then press the "Set" button to switch the upper limit, Finally, press the "Confirm" button to save the set voltage.
2. The set voltage alarm value is saved in the EEPROM of the microcontroller, with power-down save function.
3. The default upper and lower limits are H: 5.0V L: 0.0V.
4. The system has four voltage detection channels that can be detected and displayed on the display.
5. When there is one or more channels measured in the four channels, the buzzer will be alarmed when the voltage is exceeded in the set upper and lower limits.
6. Measurement range: 0.0--5.0V.
7. Set the range: 0.0--.0.0V.
Scenario: https://www.cirmall.com/circuit/1100
2, STC89C52 digital voltmeter
STC89C52 Digital Voltage Meter Resource Overview:
1. Using the ADC0809 chip to test 8 voltage
2, LCD display support LCD1602, LCD18864
3. Support sound and light alarm circuit
4, support serial debugging
Attachment contents include:
The entire digital voltmeter schematic and PCB, open with AD software;
Scenario: https://www.cirmall.com/circuit/1383
3, digital voltmeter based on ICL7135 and 89S52 single chip microcomputer
This design introduces a voltage measurement circuit based on the 89S52 single-chip microcomputer. The circuit uses the ICL7135 high-precision, dual integration A / D conversion circuit, and the measurement range is 0- ± 2000 volts, and the LCD liquid crystal module is displayed, which can be carried out with the PC. Serial communication. The body focuses on each of the partial circuits of the hardware and software system, which introduces the principles of the dual integral circuit, the characteristics of 89S52, the functionality and application of ICL7135, and the functions of the LCD1601. The circuit is novel, powerful, and strong scalability.
As shown in FIG. 2.1, after switching to a different voltage dividing circuit at different partial voltage circuit, the analog voltage is switched to a different voltage division, and then sent to the A / D conversion, and then sent to the single chip microcomputer for data processing. The processed data is sent to the LCD display, and communicate with the hostile through serial communication.
The main features of 7135 are as follows:
1 dual-grade A / D converter, slow conversion speed.
2 Before each A / D conversion, the internal circuit is automatically zeroing, ensuring the long-term stability of zero at room temperature. In the range of 20,000 words (2V full range), the conversion accuracy is 1 word equivalent to the 14Bita / D converter. Within a full range, it is ensured that the conversion accuracy is 1 word equivalent to the 14Bita / D converter.
3 has an automatic polarity conversion function. The A / D conversion of the bipolar analog input voltage can be performed at the polar reference voltage, and the analog voltage ranges from 0 to ± 1.9999V. .
4 The simulation will be a differential signal, the input resistance is extremely high, and the input current is typically 1PA.
5 All outputs and TTL circuits are compatible.
6 With OR Routing (OR) and Breeding (UR) flag signal output, it can be used as a control signal for automatic range conversion.
7 output is dynamically scanning BCD code.
8 provides six inputs, output control signals (R / H, BUSH, ST, POL, OR, UR), so in addition to the digital voltmeter, can also be used with asynchronous reception / transmitters, microprocessors or other controls. Circuit connection is used.
⑨用 Use 28 outdoor double-column insert packages.
Scenario Link: https://www.cirmall.com/circuit/4170
4, based on 51 single-chip + ADC0832 + digital tube = digital voltmeter (0-20V)
Function Description:
1. Use analog-to-digital conversion chip ADC0832 (ADC 0832 Data Manual) to collect analog voltage value
2, data calculation is performed by single-chip AT89S52 (AT89 S52 Data Manual)
3, digital tube display the measured voltage value
performance:
1, voltage measurement range 0-20V, accuracy 0.08V
2, power supply mode:
1) The 9V battery is powered, and 5V is output after 7805 regulation. This voltage is supplied with both the chip and serves as a reference voltage.
2) The standard signal source 5V is powered, (two lines under 7805, red pickup, white losing). Doing the standard signal source, the reference voltage accuracy of the ADC0832 is high and stable, so the measured voltage is quapas.
3, voltage test end. The test end is positive and negative, reverses, and 000, it is recommended to measure 1.5 dry batteries.
Scenario Link: https://www.cirmall.com/circuit/875
5. Digital voltmeter based on 51 single-chip microcomputer
This design is based on a voltage measurement circuit of the STC89C52 single-chip microcomputer. The circuit uses the ADC0832A / D conversion element to realize the hardware circuit and software design of the digital voltage meter. The digital voltage meter circuit of the system is simple, and the voltage value of 0 to 5V can be measured and the voltage value is displayed on the four LED digital tube. The components used are small, low cost, and automation can be achieved.
Scenario Link: https://www.cirmall.com/circuit/14645
6, based on the ATMEGA8 single-chip design digital voltmeter DIY production
Atmega8 Digital Voltage Table Introduction:
The digital voltmeter uses ATMEL's Mega8T32 as the main control chip, using 7133-H to control the voltage regulator output of the digital voltage meter, and the circuit is used to display the digital voltmeter measurement value using a 0.56-inch triple digital tube. This digital voltmeter measurement ranges from 3.2V-30V, and also with reverse protection, 3-bit display accuracy.
This design improvement comments:
1. Make the three-wire 0-100V voltmeter, remove R4 to change R1 to 390K, the program can be simply modified according to the original program (yourself to study)
2. Making four high-precision voltages, using the Mega8 single-chip microcomputer itself 10-bit AD to obtain 12-digit resolution to obtain a 4-digit voltage header. (Please search for yourself in Baidu Sample Principles)
3, add more practical functions such as low voltage flashing alarm, high voltage flashing alarm, etc.
4. Increase control functions Control external MOS tube or relay can be controlled according to the voltage according to the voltage.
5. Play your own imagination to create more meaningful products
Scenario: https://www.cirmall.com/circuit/1878
7,51 single-chip simple digital voltage meter is successful
The simple digital voltmeter can measure the 8-way input voltage value of 0 to 5V and the up-wheel current display or single selection display in the four LED digital tubes. The digital voltmeter (DVM) is the use of analog / digital switch A / D principle to convert an analog signal into a digital signal. Then it is displayed by the digital tube. 51 Single Chip Microcomputer Simple Digital Voltage Table is mainly composed of a single-chip + AD digital-to-analog conversion ADC0832 + digital tube display + buttons.
Scenario Link: https://www.cirmall.com/circuit/8596
8, DIY production 2 line 3 digit digital voltage meter design (schematic, PCB, source code, BOM)
The 3-bit display digital voltage form is based on atmega8, which provides a source program provided by the 3-bit display accuracy 3.2-30 V-belt reversing a voltage meter.
Improvement opinion:
1. Make the three-wire 0-100V voltmeter, remove R4 to change R1 to 390K, the program can be simply modified according to the original program (yourself to study)
2. Making four high-precision voltages, using the Mega8 single-chip microcomputer itself 10-bit AD to obtain 12-digit resolution to obtain a 4-digit voltage header.
3, add more practical functions such as low voltage flashing alarm, high voltage flashing alarm, etc.
4. Increase control functions Control external MOS tube or relay can be controlled according to the voltage according to the voltage.
5. Play your own imagination to create more meaningful products
Scenario: https://www.cirmall.com/circuit/3863
9, measure automatic switch digital voltage meter Proteus simulation + program information
74HC4066 is a silicon gate COMS four-way analog switch designed to handle analog and digital signals. The various switches of 74HC4066 allow signals to be amplitude of up to 6V (peak) for bidirectional transmission.
The respective switching units of 74HC4066 have their own enable input control (C). The high level of the C-terminal will turn on its corresponding switch unit.
The application of 74HC4066 includes signal strobe, chopping, modem, and signal multiplexing systems for analog-to-digital conversion / digital-to-mode conversion.
Scenario: https://www.cirmall.com/circuit/14126
10, single-chip DIY small voltage meter circuit solution design
This circuit is simple to make Easy STC12C2052AD microcontrollers 0-9.9V voltmeter, simple circuit, less components, easy to make, PCB boards are single-panels, and below is made. After the article, the schematic, source program and other materials are included.
Scenario: https://www.cirmall.com/circuit/9863
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