IN TOOTHBRUSHES

The first electric brush was developed in 1939 in Switzerland, but sales only began in the 1960s, under the Broxodent brand. In 1961, General Electric launched a wireless, rechargeable, electric brush with an up and down moving head. In 1987, the first rotating brush for home use appeared under the Interplak brand. Currently, many variants of this model are being produced. There are models that use not only vibrations but also ultrasound for cleaning.

Electric Toothbrushes

    VIBRATIONS IN PAGERS

At the very beginning, a popular communication device was a pager. Motorola released the first pager back in 1956. It was a one-way communication device, because the pager only allowed a user to receive messages. However, in most cases this was quite enough. The sender would call the operator of the paging company, then call the name or number of the subscriber and after that, he/she would dictate the message they want to send. A minute later, a running text line would appear on the subscriber’s pager. With the growth of popularity, pagers began to be used in those areas where one-way communication could be dispensed with. Pagers used to call emergency teams, firefighters, and police. It was convenient to use pagers on military facilities so that subscribers could not be tracked. An inexpensive device could provide residents of coastal towns and notify them of an impending storm or tsunami. So in the US, pagers began to be used everywhere, and the signal of the incoming message often woke up and distracted others. Developers decided to start borrowing technology from developing parallel toothbrushes. So the vibrations helped a user notice the message during active work, because the pagers were worn more often not in a pocket, but on a belt. In complete silence it was a much quieter polyphonic melody..

Motorola Pager

IN MOBILE PHONES

The first models of cellular and satellite phones were very cumbersome, and could not vibrate at all. The world’s first mobile phone was Motorola DynaTAC 8000x (1983). It was very heavy and angular. They could not be hidden in a pocket or worn in a holster and it was very difficult to miss a call on this phone. Engineers had to use a very powerful engine that would consume a lot of energy to integrate the vibration motor in the first phone models, and the vibration of a large bar could greatly frighten the person using the phone.

Motorola DynaTAC (1983)

Siemens A35 was a popular model of the 2000’s and still could not vibrate. In the late 90’s mobile phones became compact, inexpensive and massive. Mobile conversations went from being a luxury to an everyday occurrence. Devices at this point were already able to be placed pockets and worn by everyday people. Later, phone manufacturers began to think about the introduction of a vibration motor into mobile phones. Some phone models had such a powerful vibration that it replaced the sound of low frequencies while playing music through an external speaker. There were also reverse situations, when a good speaker played the role of a vibrator.

Siemens A35

For example, the Motorola E398 (2004), also known as ROKR E1, developed in cooperation with Apple. External speakers were head and shoulders above the competition, and there was no vibration at all. On small parties E398, could easily replace an audio system, and to enhance the sound of a phone, it was enough to put it in a small metal bowl or pan. Most Apple fans remember this phone for iTunes support. It wasn’t the most successful device, but very useful for job experience within the company. A little later vibrations were used for tactile feedback in touch smartphones. 

    Users were unaccustomed of tapping on a smooth display instead of pushing physical buttons. For this purpose, a small vibration feedback was added during the tapping. Further technological use of vibrations began to be applied relatively recently.

Motorola E398

The vibration element called the Taptic Engine already exists in most Apple gadgets. A small vibrating module is responsible for feedback in such products as the iPhone and the iPad, the Apple Watch and the Macbook (in

the touchpad ). There is no longer a classic motor with a weighting agent, but the module works thanks to the

electromagnetic induction . In the seventh and eighth generations of the iPhone, this unit also worked for the physical Home button, which has become a sensor in recent years. This is how the very simple technology evolved from the middle of the 20th century. Who knows what else they can do with smartphones in the future, all thanks to the vibration motor.

electrogenic while a fish that has the ability to detect electric fields is called

electroreceptive . Most electrogenic fish are also electroreceptive.[1] The only group of electrogenic fish who are not electroreceptive come from the family Uranoscopidae. [2] Electric fish species can be found both in the ocean and in freshwater rivers of South America (Gymnotiformes ) and Africa (Mormyridae ). Many fish such as

sharks , rays and catfishes can detect electric fields and are thus electroreceptive, but they are not classified as electric fish because they cannot generate electricity. Most common bony fish (teleosts), including most fish kept in aquaria or caught for food, are neither electrogenic nor electroreceptive.

Play media

Video of a complete electric organ discharge. The electric field potential is represented on a sagittal across the modelled fish. Hot tones represent positive potential values, while cold tones represent negative electric potentials. The black line indicates the points where the potentials are zero.

    Electric eels are fish capable of generating an electric field .

Audio recording of resting electric organ discharge of

Brachyhypopomus bennetti .

Electric fish produce their electrical fields from a specialized structure called an electric organ . This is made up of modified muscle or nerve cells, which became specialized for producing bioelectric fields stronger than those that normal nerves or muscles produce.[3] Typically this organ is located in the tail of the electric fish. The electrical output of the organ is called the electric organ discharge .

   Strongly electric fish

Strongly electric fish are fish with an electric organ discharge that is powerful enough to stun prey or be used for defense. Typical examples are the electric eel, the electric catfishes , and electric rays . The amplitude of the signal can range from 10 to 860 volts with a current of up to 1 ampere , according to the surroundings, for example different conductances of salt and fresh water. [5] To maximize the power delivered to the surroundings, the impedances of the electric organ and the water must be matched :

Strongly electric marine fish give low voltage, high current electric discharges. In salt water, a small voltage can drive a large current limited by the internal resistance of the electric organ. Hence, the electric organ consists of many electrocytes in parallel.

Freshwater fish have high voltage, low current discharges. In freshwater, the power is limited by the voltage needed to drive the current through the large resistance of the medium. Hence, these fish have numerous cells in series. [6]

Weakly electric fish

The elephantnose fish is a weakly electric fish which generates an electric field with its electric organ and then processes the returns from its electroreceptors to locate nearby objects. [7]

    Weakly electric fish generate a discharge that is typically less than one volt. These are too weak to stun prey and instead are used for navigation, object detection (electrolocation ) and communication with other electric fish (electrocommunication). Two of the best-known and most-studied examples are Peters's elephantnose fish (Gnathonemus petersii ) and the

black ghost knifefish (Apteronotus albifrons ). The males of the nocturnal

Brachyhypopomus pinnicaudatus , a toothless knifefish native to the Amazon basin, give off big, long electric hums to attract a mate. [8]

The electric organ discharge waveform takes two general forms depending on the species. In some species the waveform is continuous and almost

sinusoidal (for example the genera

Apteronotus, Eigenmannia and

Gymnarchus ) and these are said to have a wave-type electric organ discharge. In other species, the electric organ discharge waveform consists of brief pulses separated by longer gaps (for example Gnathonemus, Gymnotus,

Leucoraja ) and these are said to have a pulse-type electric organ discharge.

Jamming avoidance response

Main article: Jamming avoidance response

It had been theorized as early as the 1950s that electric fish near each other might experience some type of interference or inability to segregate their own signal from those of neighbors. This issue does not arise, however, because the electric fish adjust to avoid frequency interference. In 1963, two scientists, Akira Watanabe and Kimihisa Takeda, discovered the behavior of the jamming avoidance response in the knifefish Eigenmannia sp. In collaboration with T.H. Bullock and colleagues, the behavior was further developed.[9] Finally, the work of Walter Heiligenberg expanded it into a full neuroethology study by examining the series of neural connections that led to the behavior. [10] Eigenmannia is a weakly electric fish that can self-generate electric discharges through

electrocytes in its tail. Furthermore, it has the ability to electrolocate by analyzing the perturbations in its electric field. However, when the frequency of a neighboring fish's current is very close (less than 20 Hz difference) to that of its own, the fish will avoid having their signals interfere through a behavior known as jamming avoidance response. If the neighbor's frequency is higher than the fish's discharge frequency, the fish will lower its frequency, and vice versa. The sign of the frequency difference is determined by analyzing the "beat" pattern of the incoming interference which consists of the combination of the two fish's discharge patterns. [10]

Neuroethologists performed several experiments under Eigenmannia's natural conditions to study how it determined the sign of the frequency difference. They manipulated the fish's discharge by injecting it with curare which prevented its natural electric organ from discharging. Then, an electrode was placed in its mouth and another was placed at the tip of its tail. Likewise, the neighboring fish's electric field was mimicked using another set of electrodes. This experiment allowed neuroethologists to manipulate different discharge frequencies and observe the fish's behavior. From the results, they were able to conclude that the electric field frequency, rather than an internal frequency measure, was used as a reference. This experiment is significant in that not only does it reveal a crucial neural mechanism underlying the behavior but also demonstrates the value neuroethologists place on studying animals in their natural habitats.