Working voltage of automatic lifting lighting

Time：2021-04-01 View：

When the electrical equipment works, the actual voltage at both ends is called the working voltage. The working voltage is related to the circuit composition and the working state of the equipment and is the change value.

 

Brief introduction of working voltage
The real-time working voltage of electrical equipment usually needs to be measured by multimeter, which is an unknown value. The calculated relationship between resistance and current is: working voltage = device Resistance x work current.
The working voltage of electrical equipment needs to fall within a certain range to work normally. This range is often related to the sensitivity of electrical equipment. Generally speaking, the finer the equipment, the higher the sensitivity, the smaller the normal variation range of its working voltage. The upper limit of the normal operating voltage of the equipment is called the maximum operating voltage, which limits the range of safe potential of the equipment. The output voltage of the power system is generally required to be between 198-236v. The working voltage range of household appliances can sometimes reach 100-240V, while the working voltage of electronic components ranges from a few tens of Volt to tens of Volt, it depends on the precision of the components.

 

Different voltage differences
1. The rated voltage is a definite value, which has been set when the electrical equipment leaves the factory and is the best theoretical value; The working voltage is an uncertain value, it is a real-time change value, which is related to the actual circuit condition and the equipment status.
2. The rated voltage is a fixed value with only one single value. Generally, for the convenience of power system interconnection, all countries have made unified regulations on electrical equipment, the general rated voltage in our country is 220V and 380V; The working voltage is a variation range around the rated voltage, with countless values, allowing the voltage to fluctuate around the rated voltage when the equipment works normally, meet the needs of actual production and work.

CPU
It refers to the voltage required for the normal operation of the CPU. Increasing the working voltage can enhance the internal signal of the CPU and increase the stable performance of the CPU. However, it will cause the problem of CPU heating. CPU heating will change the chemical medium of CPU and reduce the life of CPU. In the early stage, CPU core voltage was 5V. With the improvement of manufacturing process and clock speed, the working voltage of CPU has changed greatly. Now the working voltage of commonly used CPU is 1.3-1.5V, the problem of high CPU fever is solved. When the CPU is working normally, the voltage variation range is preferably within 0.05V to ensure the performance and life of the CPU.

 

Electron Tube
The working voltage of the electron tube includes its voltage values (filament voltage, screen voltage, anode screen voltage, etc.). The voltage value of each pole of the selected electron tube should be the same or similar to the working voltage value of the circuit, otherwise the service life of the electron tube will be shortened.
When the electron tube is working, the voltage of each pole should be connected in strict order, that is, filament-bias-positive pressure-curtain grid pressure-excitation signal. The shutdown is performed in the opposite order. Among the various components of the electron tube, the filament is the most fragile, and it is better to add it gradually and in different stages when pressurizing the filament. The rated voltage of the filament varies from a few to tens of volts depending on the structure of the electron tube. The rated voltage of the filament the working voltage of the filament should be within the allowable deviation range of the rated value, usually the allowable range is 5%. If it can be kept within ± 1%, it is beneficial to prolong the service life. When the voltage of oxide cathode electron tube filament is too high, it will accelerate the decomposition of barium oxide and shorten the life of cathode; When the voltage of filament is low, barium atoms cannot spread to the cathode surface quickly, which will cause "poisoning" of cathode ", that is, the emission capability of the electron tube cannot be recovered. When the voltage of the electron tube filament of the tungsten carbide filament cathode is too high, thorium atoms in the filament will soon evaporate, shortening the life of the cathode; When the voltage of the filament is too low, the cathode will be bombarded by positive ions and become invalid. Practice has proved that transmitting tube of DC filament power supply can transform the positive and negative polarity of filament once after working for a period of time, so that the whole cathode can be evenly lost. At the same time, the electrolytic capacitor polarity of the filament input to the ground also changes, which is helpful to prolong the service life of the pipe. For tubes with known service life, the power decreases due to insufficient cathode emission, which can appropriately increase the working voltage of the filament and plus-sized the filament current to prolong the service life.

electronic chip
At present, the operating voltage of most DSP chips and MCU is 5V, and some are as low as 3V or even 1.5V. The lower the voltage, the smaller the width between lines within the allowable distributed capacitance capacity. In this way, more components and lines can be integrated on a 1 mm²-chip.

 

Electronic and electrical products
Before leaving the factory, electronic and electrical products usually need to conduct some column tests on the working voltage to determine the safe potential range of the products. When testing the working voltage, attention should be paid to the following aspects to improve the accuracy of the test results:
1. The exchange of power polarity indirect method has a great influence on the test results of working voltage. During the test process of working voltage, the influence of the positive or reverse connection of the plug on the test results should be considered. It is suggested to select the "maximum working voltage value" measured in the two states as the final test results;
2. TN-S the power supply network has an impact on the working voltage test results, especially whether the power supply equipment and the test sample are connected together cannot be careless;
3. The oscilloscope must be grounded during the measurement of working voltage;
4. Differential probe is adopted to make the grounding oscilloscope can carry out floating measurement, and the probe system is isolated from the chassis Earth end of the oscilloscope as a whole;
5. In the testing process of peak working voltage, the selection of oscilloscope sampling mode plays a decisive role in the measurement accuracy of working voltage;
6. If the output signal is non-sine wave signal, the measured value of the working voltage must measure its true effective value, however, to measure the true effective value, it is necessary to require the inside of the instrument and meter to have chips or circuit models that can realize this signal operation;
7. The larger the input impedance, the higher the accuracy of the test value.