The difference between the live wire and the neutral wire is that they have different voltages relative to ground. First of all, we can use color to distinguish: in power cables, green and red represent phase A, phase B and phase C (three-phase live wire), blue represents neutral line and yellow and green represent the ground wire. .
The second is to use tools such as electric pens or multimeters. For example, when the live wire is tested with an electric pen, the neon tube will glow, but the neutral wire will not.
It is also possible to use a voltmeter. Use a voltmeter to distinguish: the voltage between different phase wires (i.e. live wire) is the line voltage 380V, the phase wire (live wire) and neutral wire (or a good grounding body) The voltage between them is a phase voltage of 220 V and the voltageone between the neutral line and a good ground is 0 V.
Insert clean copper foils and zinc foils (which can be peeled off from old, dry, washed batteries) separately on the lemon (do not do not touch them together), and a pile of fruit is made. The copper foil is the positive electrode of the battery and the zinc foil is the negative electrode. Connecting more in series can increase the voltage, and connecting in parallel can increase the current.