The function and significance of the pulse capacitance voltage divider

Author： GOZ Electric Time：2013-03-26 14:19:42 Read：28

    On the basis of introducing the basic principles of capacitive voltage divider, the relationship between the pulse signal time and the time constant of the capacitive voltage divider measurement system is analyzed. The equivalent circuit diagram of the voltage divider is established, and the measurement system is simulated and analyzed. The analysis shows that the parasitic inductance and capacitance in the capacitor have a greater impact on the voltage divider. When they reach a certain extent, the system output waveform will vibrate violently, the rise time becomes longer, and the output waveform is distorted [1]. The resistance in the capacitor has a certain influence on the performance of the voltage divider, and appropriate consideration should be given when designing a high-voltage pulse capacitor voltage divider. By changing the various parameters in the equivalent circuit, analyzing the influence of different parameters on the measurement performance of the voltage divider, the structure of the voltage divider is optimized.

Keywords: Voltage divider; Capacitor voltage divider; resistor voltage divider ; Voltage measurement; response time；

       1). Study the function and significance of voltage divider

    　　Converting a high-voltage signal into a low-voltage signal that can be measured by an oscilloscope occupies an important position in the entire test system. The performance of the voltage divider directly affects the overall performance of the test system. As a conversion device, the voltage divider is one of the main components commonly used in impact measurement systems. Its role is to convert the shock high voltage of tens of thousands of volts or hundreds of thousands of volts into a low voltage that can be measured by a recorder such as an oscilloscope. Old-fashioned high-voltage oscilloscopes can apply up to 1KV-2KV, while general-purpose digital storage oscilloscopes can generally only add tens of volts or a few volts, so high voltage divider the high voltage must be converted into tens of volts or a few volts through a high-voltage voltage divider before it can be input to the coaxial cable, and a few hundred millivolts can be input to the coaxial cable through the coaxial cable.A voltage of tens of volts is transmitted to a digital oscilloscope for measurement.

       2). Pulse Divider Measurement should meet the requirements [2]

(1) After the parts of the measured voltage waveform are scaled down, the waveform has no distortion;

(2) The partial voltage ratio is constant, and within the scope of application, it does not change with the atmospheric conditions or the waveform, frequency, amplitude and other factors of the measured voltage;

(3) The influence of the access of the voltage divider on the measured voltage process should be small to the allowable extent.

      In addition, the voltage divider should not consume much electrical energy. Under certain cooling conditions, the temperature rise formed by the electrical energy consumed by the voltage divider should not cause a change in the partial pressure ratio. The voltage divider ratio should be independent of the frequency and amplitude of the measured voltage within a certain frequency range.