The main parameters of the discharge tube: first discharge tube type ceramic gas discharge tube and semiconductor discharge tube. Ceramic gas discharge tube to test parameters:
1 DC breakdown voltage: 100 V / s for voltage test.
2 impact breakdown voltage: 1KV/uSl to test.
3 Nominal impact discharge current: rated current of 8/20uS waveform
ITU-T recommendation: discharge 10 times
GB9043 requirements: discharge 10 times Put the main technical parameters and using the selected tube:
1 DC discharge voltage
In the higher gradient voltage lower than the effect of 100V/s, the average discharge voltage discharge value is called the DC discharge voltage. Due to the dispersion of the discharge, the DC discharge voltage is a numerical range.
2 impulse discharge voltage
The regulations has increased the steepness of the transient voltage pulses, the discharge start voltage discharge value is referred to as the impulse discharge voltage.
Pulse discharge tube of response time or action delay time and voltage rise related to the steepness and for different higher gradient, impulse discharge voltage of the discharge tube is different.
3 power frequency withstand current
Discharge tube through the power frequency current 5 times, so that the DC discharge voltage and insulation resistance of the tube no significant change in the maximum current is known as its power frequency withstand current.
4 impulse withstand current
The discharge tube through specified waveform and the required number of pulse current, the DC discharge voltage and insulation resistance does not occur significant changes in the maximum peak current said tube impulse current tolerance.
This parameter is in certain waveform and through the times given, manufacturing plant is usually given in the 8 / 20 US waveform through 10 times the impulse withstand current to flow in the flow, there are also given in 10/1000us waveform under the through flow 300 times of impulse current tolerance.
5 insulation resistance and capacitance
The insulation resistance of the discharge tube is very large, and the factory is generally given the initial value of the insulation resistance. The decrease of the value of insulation resistance will lead to the increase of leakage current, which may cause noise interference.
The parasitic capacitance of the discharge tube is very small, the capacitance between the poles is generally in the range of 1pF ~ 5pF, and the pole capacitance is approximately constant in a very wide frequency range, and the dispersion property of the pole capacitance value of the same type discharge tube is very small.
6 selection of DC discharge voltage
Never influence protected the normal operation of the system requirements, to DC discharge voltage discharge was higher. But the DC discharge voltage of the tube, the impact of the discharge voltage is also high;
From the protection of the electronic equipment tolerance, the hope that the DC discharge voltage of the tube is low.
Therefore, the discharge voltage of the discharge tube should be made a compromise between these two kinds of constraints.