20 1 1 the principle of revealing the magic in the Spring Festival Evening: the positive reaction of fish
In a certain DC electric field, the fish will turn to the anode and swim to the anode. Even if the current direction is changed, the fish will turn to the anode. In an alternating current field, the fish will stagnate.
This directional induction response of fish to electrical stimulation is called positive response, and the minimum or critical voltage corresponding to the positive response of fish is called positive voltage.
The induced voltage of fish with head facing the sun is 1.5-2.0 times that of fish with tail facing the sun.
Stimulate the fish with the middle value of the induced voltage at the head and tail: when the fish head is facing the anode, the fish has no induction reaction, but when the fish tail is facing the anode, the fish will have induction reaction. This is the reason why fish move to the anode in the electric field (that is, positive reaction), which is an instinctive reaction of fish to alleviate the pain caused by electric shock.
Big fish are sensitive to low-frequency pulse current, and small fish can produce the same positive reaction only when the pulse frequency is slightly higher.
When fish are stimulated by high-frequency pulse current, they often can't get effective positive response. Generally, the most suitable pulse current frequency for fish to produce positive reaction is about 40 Hz.
The positive pulse frequency of anchovy sardines is 25-45 Hz; 25-45 Hz for minnows; Japanese anchovy 25-45hz；; Jellyfish is 35 Hz; Flounder 20-40 Hz; Carp 45-50 Hz
When the fish is stimulated by pulse current with fast rising and slow falling waveforms, the fish will have a positive reaction immediately. The faster the current increases, the lower the voltage for the fish to produce a positive reaction.
When the fish is stimulated by the pulse current with slow increase and rapid decrease in waveform, the fish's nerves adapt to the current when the current slowly increases, so the phenomenon that electrical stimulation does not work appears.
According to the response effect of fish to the change of pulse current waveform, pulse deformation with rapid increase of current and slow decrease of current is generally adopted.
The greater the intensity of electrical stimulation to fish, the shorter the discharge time. Usually, the pulse period of fish electrotherapy is controlled within 2 milliseconds.
The pulse time of freshwater fishing is1.5-3 ms; The pulse time for expelling fish schools is 0.5- 1 millisecond.
Analysis on the process of three fishes being attracted to the aquarium;
The three big goldfish in the aquarium were put in advance, and there was a piece on the top of the aquarium. You can see that the block size of the aquarium is much higher than that of the general aquarium, and it is a colored white strip. In order to block people's sight. There is a switch. Goldfish will fall into the water by themselves. Look at the magician's finger in the picture. One of his two hands (the upper hand) has a big finger at the back of the picture. He is operating three fake fish. In the painting.
The last bubble in the aquarium. There is more carbon dioxide in an aquarium than in an ordinary aquarium. He deliberately put it together and let the water stir, so that all the goldfish fell into the water. . .
Secret newspaper:
On the back of the newspaper, another complete newspaper was folded. When the newspaper was torn open, it was already broken, but there was a complete newspaper in the corner. When he tore it all apart, he opened the pre-folded newspaper. Another complete newspaper.