东莞市沃格精密电器有限公司

We often say that the fuse has this or that purpose, then the quality of the fuse for the main criteria and testing, respectively, what is it?

There are many ways to measure the capacity of the fuse. Can be based on the fuse discharge curve, short work discharge, a lot of low-quality fuse discharge voltage is also very stable early, once into the late, the voltage drop is very agile. This current is called the 10-hour rate of current (weigh the exhaustion of the specification, can not be the fuse discharge voltage is reduced to zero whichever fuse over discharge, so the use of this approach will be very straightforward conclusion The most reliable and accurate to the same as to standardize the discharge of electricity, the whole process of measuring the discharge method of divergence of the discharge current, the fuse can eventually release the power is different, there is a certain gap between the fuse capacity are marked Consistent with the current use of the most is the 10-hour rate of discharge capacity and 20 hours rate discharge capacity of two.10 hour rate discharge capacity is the fuse to a constant discharge of electricity to the exhausted power consumption can be maintained for about 10 hours will lead to Fuse cut, can not be restored, or even premature damage, completely ineffective.

So each fuse discharge termination voltage has a strict rules, this can refer to the relevant materials. Measurement process if the 10-hour rate of current to continue to discharge at least 5 hours or more, so that the test of such a long time more need for patience and spirit and surplus time. Technology to carry out the long and quick agility, today's microcontroller has been very popular. After the single-chip control of the discharge time, the depth of the initiative to control, it is easy to accurately measure the actual capacity of the fuse to complete the process of active control. Although the practice of discharge measurement capacity of the method of power is a little waste, but on the 1A, 2A below the small-capacity rechargeable fuse is still feasible, large-capacity battery sampling is also a need for reflection. Over-discharge and over-charging is the formation of circuit fuses can not reach the useful life, the first cause of early retirement).

Timely discharge of the measurement method is the biggest drawback is time-consuming, due to the long time-consuming measurement accuracy is also very easy to be affected by various types of external factors. So the practice of testing the fuse discharge criteria still as fast as possible, only need to get a rough fuse. In order to complete the fuse process faster, the circuit design here uses two hours of current to discharge. After the consequences of the fuse compared to the difference, the capacity of the difference is so self-evident, as a trade-offs of the fuse is good enough, it was enough. Here to 1000mAH, 1.2V specifications Ni-MH fuse test, for example, discharge current 500mA on the need to use 2Ω discharge resistance. The following shows the battery capacity tester using 89S51 as a control chip, is the hardware circuit diagram.

The fuse tester by the discharge circuit, single-chip control timing two completely self-local combination. SCM local manufacturing time and effort, and the market situation has been very popular single-chip, R1 can use 3296 series of fine adjustable potentiometer. 3296 multi-turn adjustable fine potentiometer adjustable in the general 50T, so the regulation of each lap is limited to 2%, once for each change, the resistance change of about 0.005%, so it is easy to adjust to obtain an accurate, constant resistance The No need to personally create, free to find a 51 single-chip implementation of the board on it. Discharge circuit is relatively simple, only four or five components. The main part of the microcontroller as the discharge time, and ultimately get a solid set of data for the fuse function considerations.

The essence of this discharge circuit is to imitate the thyristor and then roughly derive the fuse capacity. The biggest advantage of this approach is rapid, but the charging fuse discharge curve is not universal. When we will be tested fuse access circuit response status, click the start button, if the fuse otherwise margin, the fuse discharge voltage will remain above the set value, the transistor VT1 will be instantly saturated, the fuse through the resistance R2 Discharge. This circuit has a reliable and accurate steep switch characteristics, VT1 absolute task in the saturation of the two under the form. Through the adjustable resistance to the switching circuit threshold (that is, the fuse discharge termination voltage) to adjust the settings, can be adapted to all types of different types of fuse to maintain the full discharge. Because the use of personal does not require very accurate test results, the fuse discharge voltage should be controlled at 1V or more. The discharge termination voltage is adjusted by the adjustable resistor R1. Popular adjustable resistance accuracy is poor, and prone to drift, will lead to set a good termination voltage with the passage of time and the use of changes in the situation occurred larger shake. In order to ensure that the discharge termination voltage is accurate and easy to set.