Simple withstand voltage tester, WITHSTANDING VOLTAGE TESTER
Keywords: simple withstand voltage tester
Simple pressure resistor
E-enthusiasts often require the pressure of the components such as diode, triode. This article describes a simple and easy tolerant tester. It only requires two 1.5V battery power supply, which can output the test voltage of 200V to 1300V, which can basically meet the needs of common diodes and triode withstand voltage tests. See the drawings in the drawings.
This circuit is a common single tube pulse oscillator. V is the NPN power tube, and its power does not need to be large. 3W-5W can be, but β is better. Since it is not a continuous work, no heat is added. The potentiometers RP and R1 are connected in series to adjust the output voltage, the adjustable range of 200V to 1300V, and the corresponding power supply current is 70 mA to 450 mA. When the switch K is pressed, the circuit starts, the C pole anti-peak voltage of V is about 10 volts, and the transformer is rising to 1000V. Three FRL07 fast recovery tubes are connected in series, and the back pressure can reach 3000V for 1000V high pressure rectification, and the filter capacitance of two 0.11uf / 630V is also connected in series to obtain a pressure of 1300V or more. After the output voltage is currently currently currently currently being limited, on the pending element in parallel with the voltmeter, the tested element is in the reverse breakdown state, i.e., directly read the reverse withstand voltage. Voltage meter can be available with a number table 1000V, or a pointer table for 10kΩ / V or more. Since the internal resistance of this power is large, even if there is no R2 current limit, the current is only LMA - 2mA, so there is no need to worry about the damage to the device. Before each measurement, it is best to adjust the voltage to the lowest, and then slowly increase, and when the voltage meter reads no longer rises with the potentiometer, it is the reverse pressure of the component to be tested. . When the device is counter-pressure, the voltage meter can change the low pressure stop test.
The key to the success of the tester is the winding of the transformer. The author used the E-iron oxygen core of the waste 9W energy-saving lamp. Remove the original windings on the frame, you can re-press the data from the drawings. When winding, the same direction is, and the start end. The secondary coils have a voltage higher than 1000V above, and the winding should be paid to the insulation. The author uses the segmentation winder, which is the farthest distance, and a method of layered an insulating film can also be used.
According to the test of the semiconductor component reverse withstand voltage, it should be tested under the rated reverse current. The reverse current of this tester is not fixed, but the higher the reaction pressure, the smaller the reverse current, although it may cause a certain error, but is still possible under amateur conditions. In particular, as the element quality is improved, its reverse leakage current is close to zero, and the effect on the reverse breakdown current is extremely small. The error of the pressure to measure the pressure is smaller.
Incidentally, this back pressure tester has another two uses. The first is to measure the pressure about the capacitance of polyester, polypropylene, porcelain. The method is that the capacitance to be tested is connected in parallel with both ends of the voltmeter, and the output voltage is gradually increased from low to the low, and the required voltage is not broken. Do not blindly increase the voltage, otherwise the capacitor will be broken, causing permanent damage. The second is to use as a megaus table to determine insulation resistance. At this time, the output voltage can be set to 500V or 1000V, and then find a 500V or 1000V voltage meter that is known internal resistance and the resistance to be measured, and then the voltage output of the tester can be used, that is, according to the number of voltmeter. The size of the resistance to be measured can also be directly used to scale the instrument test using the electric resistance block of the multimeter.
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