Explore the role of the human body in the electric pencil circuit
In order to explore the role of the human body in the electric pen, I did the following experiments:
1. Hold the electric test pen, the tip of the pen touches the live wire, the metal body at the end of the test pen touches the human body, and the neon tube glows.
2. Hold the test pen, the tip of the pen touches the live wire, the metal body at the end of the test pen is separated from the human body, and the neon tube does not emit light.
3. The human body sits on a wooden chair, holds a test pen, the tip of the pen touches the live wire, and the metal body at the end of the test pen touches the human body, and the neon tube glows.
4. The human body sits on a wooden chair, holds a test pen, the tip of the pen touches the live wire, the metal body at the end of the test pen separates from the human body, and the neon tube does not emit light.
Through steps 1 and 2, it can be seen that in the test pencil circuit, the human body acts as a conductor and becomes a part of the circuit. Without the human body, the measuring pen cannot form a circuit.
Through steps 3 and 4, the human body acts as a conductor, and its resistance cannot be compared with that of a wooden chair. The resistance of a human body is only a few thousand ohms, while a wooden chair can be regarded as an insulator, and its resistivity is greater than that of air. The current should be very weak. But in step 3, the neon tube still glows, which shows that the human body is testing the electric pen circuit, which is a conductor, not a simple conductor. To this end, I have carried out the following operations:
5. Hold the electric test pen, the tip of the pen touches the live wire, the metal body at the end of the test pen is directly connected to the earth (or floor ground) through the wire, and the neon tube does not emit light.
6. Hold the electric test pen, the tip of the pen touches the live wire, the metal body at the end of the test pen is connected to the leather shoes through the wire, the leather shoes are placed on the ground (or the floor ground), and the neon tube does not emit light.
In step 5, the resistance of the wire is much smaller than the resistance of the human body, and in step
In step 6, the resistance of the leather shoes is similar to that of the human body, but in the two experiments, the neon tube of the electric pen does not emit light, which shows that the function of the human body in the circuit of the electric pen cannot be simply explained by the conductor. In order to clarify the role of the human body in measuring the electric pen circuit, the following operations were carried out:
7. Unscrew the metal screw at the end of the test pen, connect a wire, then screw on the metal screw at the end of the test pen, and connect the other end of the wire to a "22O V 330 F" capacitor (removed from the computer power supply) On the pole, hold the insulating part of the test pen with one hand (do not touch the metal of the pen tip or the metal of the pen tail), hold the capacitor with the other hand, and then touch the tip of the test pen with the live wire, and find that the neon tube glows. But darker.
8. Take your hand away from the capacitor and find that the neon tube does not emit light.
9. Touch the other pole of the capacitor with your hand, and you will find that the neon tube glows brighter than step 7, which is almost the same as when people directly touch the metal body at the end of the pen. From this point of view, in the test pencil circuit, the human body is a large electric circuit.
Capacity, and there are complex electrochemical reactions inside the human body. When the human body is in contact with the live wire through the electric test pen, the live wire is charged and discharged through the electric test pen and the human body. Due to the existence of high resistance, the charge and discharge current is relatively small, but it is enough to make the neon tube glow.
