Introduction of Multi-function Electric Test Pen
(1) Check whether the filaments of light bulbs and fluorescent tubes are burned out. When ordinary frosted glass or colored incandescent lamps and fluorescent tubes for household use cannot emit light normally, it is impossible to directly see with the naked eye whether the filament (tungsten wire) inside has been burned out. A judgment can only be made through methods such as multimeter testing. But as shown in Figure 10, one hand can hold one electrode end of the incandescent lamp (or fluorescent lamp), and the other hand can hold a measuring pen (note that the finger should touch the electrode), and touch the other electrode end of the incandescent lamp (or fluorescent lamp) through the detection electrode. If the LED inside the test pen lights up, it means that the filament has not been burned out, and the tested incandescent lamp (or fluorescent lamp) is good; If the LED inside the test pen does not light up, it indicates that the internal filament of the tested incandescent lamp (or fluorescent lamp) has burned out and can only be scrapped and replaced with a new one. This method of detecting whether the filament has burned out is simple and fast, and is very useful in troubleshooting lighting circuit faults.
(2) Check if the casing of the electrical appliance is leaking electricity. The metal casing of electrical appliances must maintain good insulation with the two electrodes of the power plug, otherwise electric shock accidents may occur when the human body touches the powered electrical appliances. The method shown in Figure ll is to use a measuring pen to detect whether the outer shell of a soldering iron leaks electricity. Pinch the electrode of the power plug of the soldering iron with one hand, and hold the measuring pen with the other hand (note that the finger should touch the touch electrode of the hand), and touch the metal shell of the soldering iron through the detection electrode. If the LED inside the measuring pen does not light up, it indicates that the insulation performance between the metal shell of the soldering iron and the internal circuit is good; If the LED inside the measuring pen lights up, it indicates that there is a serious leakage phenomenon between the internal circuit of the soldering iron and the metal shell. It must be used after troubleshooting the soldering iron. The testing methods for other electrical appliances are the same.
(3) Detect the continuity of coils such as inductors and transformers. As shown in Figure 12, hold a measuring pen (note that your fingers should be in contact with the analog pole) and use the probe of the measuring pen to touch one end of a coil such as an inductor or transformer. Pinch the other end of the coil with the other hand. If the internal LED of the measuring pen lights up, it means that the coil is connected; If the internal light-emitting diode of the measuring pen does not light up, it indicates that the coil has already been opened internally.
(4) Determine the polarity of the diode. As shown in Figure 13, directly pinch one end of the diode with your hand, touch the touch pole of the measuring pen with your other hand, and use the probe pole to touch the other end of the diode. If the internal light-emitting diode of the measuring pen emits light, it means that one end of the hand grip is the positive terminal of the diode, and the end of the measuring pen probe in contact is the negative terminal; If the LED does not emit light, it means the situation is exactly the opposite. The hand holding one end of the diode here is equivalent to the black probe used to determine the polarity of the diode using the ohm range of a pointer multimeter, while the probe of the measuring probe is equivalent to the red probe. Having mastered this law, one can also use a measuring pen to determine whether the resistor is open, as well as the polarity of transistors, thyristors, and other devices. Readers can use their brains and hands to summarize the specific methods, which will not be elaborated here. Due to the use of two hands instead of commonly used measuring probes, it is more convenient to operate than a multimeter.
