What is the method of use of a digital pen?
(1) Button Description:
(A key) SELECT, directly measure the button (far from the LCD screen), that is, when using the pen to directly contact the circuit, please press this button.
(B key) INDUCTANCE, induction measurement button (closer to the LCD screen), that is, when using the pen to sense contact with the circuit, please press this button.
Note: Regardless of how the pen is printed, please remember that the one far away from the LCD screen is for direct measurement; The sensor key is located closer to the liquid crystal.
(2) The digital measuring pen is suitable for directly detecting AC and DC currents ranging from 12 to 250 V, as well as indirectly detecting the zero line, phase line, and breakpoint of AC currents. It can also measure the on/off of uncharged conductors.
(3) Direct detection:
① The last digit represents the measured voltage value.
② When the high break display value is not 70%, the low break value is displayed.
③ When measuring direct current, touch the other pole with your hand.
(4) Indirect detection: Hold down the B key and place the pen tip close to the power cord. If the power cord is live, the display of the digital pen will display a high voltage symbol.
(5) Breakpoint detection: When holding down the B key and moving longitudinally along the wire, the absence of any display in the display window indicates the breakpoint.
Why does the zero line of the test pen not emit light
Not only is there current passing through, but it is also equal in magnitude to the current in the live wire, because the zero wire is connected in series with the live wire and the electrical appliance, and the current in each part of the series circuit is equal. I don't believe it, just use an ammeter to measure it. As for why it cannot be measured with a test pen, it is simple because the test pen is used to distinguish between the live wire and the zero wire, or to determine whether a conductor is connected to the live wire, and cannot determine whether there is current. When the metal body of the stylus tip contacts the live wire or a conductor connected to the live wire, a circuit is formed from the live wire through the stylus, the human body, and the ground. Because there is a 220V voltage between the live wire and the ground, a weak current flows from the live wire through the stylus and the human body to the ground. The neon tube of the stylus emits light, but it is not the same as the current in the live wire. When the metal body of the stylus tip contacts the zero line, there is no voltage between the zero line and the ground, so there will be no current flowing through the stylus, and the neon tube of the stylus will not emit light.
