How does the withstand voltage tester work?
Working principle: The measuring circuit is shown in Figure 1. After the 6V of the transformer T is D5 rectified and C3 filtered, the base voltage of the adjustment tube Q is provided. Adjust W to control the degree of conduction of Q. That is, the control collector A point changes the voltage between 4V and 1400V. The 500V voltage output from the high voltage winding is rectified by a voltage doubler rectifier circuit composed of C1, D1-D4, and the C2 filter output is 1400V high voltage. During the test, the device under test is connected between A and B. When the resistance value of W is small, the base potential of Q decreases, and the potential of point A rises. Until the milliampere meter indicates the rated reverse current of the tube under test (the measured small power tube <0.1mA, high power tube <1mA is appropriate). At this time, the voltage value indicated by the voltmeter is the back pressure at the reverse current. When measuring the resistance value, the resistance is connected between A and B, and the voltmeter reading is divided by the milliampere meter reading. Unit: Ω=V/A. After each run out, set W to maximum and return the output voltage to the low 4V.
The device can conveniently measure the back pressure of the triode, the diode, the Zener tube, the thyristor, etc.; the capacitor withstand voltage; the resistance is greater than 10 MΩ. The output voltage is continuously adjustable up to 1400V.
Component selection
Q requires β ≥ 5, BVcbo ≥ 1500V, and reverse leakage current <0.01uA at Ic=1A. It can be selected from high pressure pipe such as C1942, C2027, BU208, and heat sink. T is a tube radio power transformer, available in the flea market.
The internal resistance of the voltmeter is 10kΩ/V or more. It is best to have: 1500V, 500V, 250V, 50V, 10V several files. The milliampere meter should have two steps of 0.5mA and 5mA. Can be replaced by a multimeter. Pay attention to the insulation between the circuits when making.
Test items
The performance indicators are tested using a dedicated Ethernet test instrument, and the test results of these performance indicators can also evaluate whether the LAN system meets the acceptance requirements. From GBT21671-2008 "Ethernet-based LAN System Acceptance Evaluation Specification", it can be understood that LAN can also judge performance by measuring performance indicators such as network throughput, transmission delay, and packet loss rate. The Ethernet tester is a rugged test platform suitable for field use. It has a complete Ethernet test function, dual optical ports and dual electrical ports, Ethernet service interface module, HST-3000 supports multiple data stream tests. Including 10/100/1000M Ethernet link traffic generation and troubleshooting, it can test electrical and optical port links up to 1Gbit/s. Due to the limitation of various conditions in the acceptance inspection, point-to-point or routing network testing can be supported for routine testing of switches.
The problem
The overall characteristics of modern test instruments are high reliability, high performance and high applicability. Therefore, the gap between domestic test products and foreign products is reflected in this aspect. Although some domestic testing equipment is close to the international advanced level in certain performance indicators, there are generally few products with comprehensive equipment performance indicators that meet international standards. In addition, most of the domestic test instruments are common specifications, which cannot meet the test work in some special environments. Low-level automated testing is also a common problem. [3]
Switch test technology
Nowadays, switches put forward new requirements on the performance of switches based on application requirements. There have been new developments in comprehensive network services, security, and intelligence. Protocol testing is a basic switch testing technology. The network protocol is to improve the efficiency of testing and the effectiveness of communication to ensure the rules of communication. In the era of increasing network communication, network protocols are also indispensable. The basic requirements of network protocols are correct functions, good interoperability and superior performance. The initial prototype of protocol testing is software testing, and the main categories are black box testing, white box testing and gray box testing.
Ethernet Switch,Web Management Switch,Non-Web Management Switch,Reverse Power Switch,10G Switch,Combo Port
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