Shaking hands and multimeters are essential measurement tools for electricians' daily maintenance and operation. However, in addition to routine use of these two types of watches, the following two methods of use may not be known by many people. 
Let's start with the multimeter:
Measurement of basic parameters such as voltage, current, resistance, capacitance, and transistor is a basic function of a digital multimeter.
Wire and cable insulation is good, the method of measuring the core wire break
If the wire or cable insulation breaks down when a good core wire breaks, connect one end of the wire or cable with a breakpoint to the live wire of 220V and the other end is left unconnected. Pull the digital multimeter to AC2V block, starting from the wire access terminal of the wire or cable, holding the pen tip of one of the pens with one hand, and the other hand slowly moving the pen tip of the other pen along the insulation of the wire or cable. When moving, the voltage value displayed on the display of the multimeter is about 0.445V. When the test pen moves to a certain point of the wire or cable, the voltage displayed on the display screen suddenly drops to about 0.04 volts, and then the place where the wire and the cable are disconnected is about 15 cm away from the movement of the pen.
This method is the principle of electromagnetic conversion. Since it is not a complete current loop, the sensed voltage is very small. If the wire is shielded, the shielding layer shields the weak magnetic field around the core wire and the multimeter does not detect it at all, regardless of whether the wire is broken.
Megohmmeter (rocking table):
The dynamic and static contacts in the fluorescent lamp starter bulb are broken. After the starter's two poles pass 220V, the xenon ionization in the bulb generates glow, which causes the temperature of the dynamic and static contact pieces to increase and expand. After the starter is turned on, the two poles of the starter are equalized, and the glow discharge is no longer in the helium bubble. After the temperature is lowered, the dynamic and static contacts contract and break.
We can use 500V megger to measure the starter, connect the two ends of the fluorescent lamp starter to the two terminals of the megohmmeter, and then gently shake the handle of the megohmmeter. If the starter has red light, Flashing, indicating that the starter is good, no red flash can be judged to be short circuit in the starter capacitor or the static and dynamic contacts in the bubble stick together.
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