The working principle of magnetic detection is that some parts of the large denomination real banknotes (20, 50, 100 yuan) are printed with magnetic ink, and the magnetism of the moving banknotes is detected by a set of magnetic heads, and the magnetism is analyzed through the circuit, which can be distinguished The authenticity of the banknotes.
In magnetic detection, good friction between the magnetic head and the banknote is required. If the head is too high, the impact signal will be large, causing false alarms; if the head is too low, the signal will be weak, causing false alarms. The detection needs can be met by controlling the height of the magnetic head (guaranteed by processing and assembly) and installing a banknote pressing rubber wheel above the magnetic head.
The magnetic detection methods of RMB can be divided into four types:
⑴Check whether there is magnetism. Most banknote counters on the market use this method. Because of the ease of manufacture, the detection rate of counterfeit banknotes in this method is low.
⑵ What to do to detect magnetism according to the magnetic distribution. Two or three sets of magnetic heads are used to detect magnetism in a branch, and the level of forgery identification can be raised to a level. Some currency counters on the market use this method.
⑶ Detect the magnetism of the fifth edition of RMB metal wire The current level stays at detecting the presence or absence of magnetism. According to our observations on the oscilloscope, the magnetism of the metal wire is a very regular rectangular wave, and the magnitude is also very accurate. Because it is difficult to imitate, if this feature can be used in the magnetic detection, it will greatly improve the level of forgery.
⑷ Detect the magnetism of the fifth edition RMB horizontal code. The current level stays at detecting the presence or absence of magnetism. Because the horizontal number is a set of numbers with certain magnetism, if the number and size of the magnetism of the horizontal number are detected, the level of forgery can be greatly improved.