The functions of the electroscope: 1. Low-voltage electroscope, used to test low-voltage electrical equipment with a ground voltage of 1000V and below, and is also a commonly used electrician safety tool in the home; 2. High-voltage electroscope, mainly used To test high-voltage electrical equipment with a ground voltage of more than 1000V, three types are currently widely used: luminous type, acousto-optic type and windmill type.
#The operating environment of this tutorial: Windows 11 system, Dell G3 computer.
What is the function of electroscope?
1. Low-voltage electroscope: It is used to test low-voltage electrical equipment with a ground voltage of 1000V and below. It is also a commonly used electrician safety tool in the home.
2. High-voltage electroscope: High-voltage electroscope is mainly used to test high-voltage electrical equipment whose ground voltage is above 1000V. Three types are widely used: luminous type, sound and light type, and windmill type.
An electroscope is an instrument that detects whether an object is charged and roughly estimates the amount of charge. When the object being inspected comes into contact with the conductor at the top of the electroscope, its charge is transferred to the foil inside the glass bell. Since like charges repel each other, the foils will automatically separate and open at an angle.
The charge level of the object can be estimated based on the angle between the two foils. In fact, this is the electric field force exerted on the foil, including the repulsion of the charges with the same name on the foil and the attraction of the charges with the same name on the inner wall of the vessel.
If the glass bottle is replaced with a metal box to shield against static electricity, wires are drawn from metal rods and vessels to measure the potential difference between two points, and a scale is added to quantify the results, the electroscope can be transformed into a more accurate electrometer .
Extended information:
Troubleshooting of the electroscope:
1. Press the test button on the high-voltage electroscope. The European meter alarm sound is very small. Use a voltmeter to measure the voltage between pin ⑦ of HD14011BP and ground, which is 9V. It is normal. The peripheral components of HD14011BP were checked and all were normal. After checking the transistor Q2, it was found that its performance was poor. Replace it with a C9014 and the fault was eliminated.
2. Press the test button on the high-voltage electroscope and press the ceramic plate and light-emitting diode without alarm.
According to the fault phenomenon, it is judged that it is the front-end flat rubber-sheathed flexible cable. The source trigger control circuit Q1, R1, R2, and R3 should be detected for damage. Use a multimeter to check the above components. They are all normal. Then check again. After checking the peripheral components of HD14011BP, no problem was found. It was judged that HD14011BP was damaged.
3. Press the watch-type near-current alarm and test button on the high-voltage electroscope. The intermittent flashing light emitted by the light-emitting diode is normal, and the alarm sound emitted by the piezoelectric ceramic piece is checked. Q3, R10, R11, L are normal. The connection line between the piezoelectric ceramic chip and the circuit board is good. Replace the piezoelectric ceramic chip and troubleshoot.
High-voltage electroscope, electric sliding wire rheostat, must be inspected regularly. When using it, handle it with care and do not shake or vibrate violently. It should be placed in a fixed cabinet and should not be placed in places with moisture, power test wires, or dirt. Avoid placing ultra-low-frequency high-voltage generators in environments containing corrosive air (such as acid, alkali and other gases). High-voltage electroscopes should undergo preventive testing every six months.
If it is found that the shell of the electrical test indicator is defective or the insulating rod has cracks or other obvious defects, it is not appropriate to conduct preventive tests and should be replaced in time.
4. When you press the test button on the high-voltage electroscope, the alarm is normal, but the audio alarm does not sound when using the electroscope to test electricity.
Press the test button on the high-voltage electroscope, the pressure ceramic piece and slide wire indicator light-emitting diode alarm are normal, indicating that the HD14011BP internal circuit and drive circuit, piezoelectric ceramic piece and light-emitting diode are normal, and the fault is in the front-end induction The detection source triggers the control circuit. Use a multimeter to check Q1, R1, and R2 and find that the resistance of R2 has increased to 4MΩ. Replace it with a 1MΩ resistor and the fault is eliminated.
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