
Arirang (Korean: 아리랑) is a line of North Korean Android smartphones. They were announced on 10 August 2013. The phone was distributed to local sales points operated by mobile operators such as Koryolink to be sold together with 3G SIM cards or as a stand-alone device. It is named after the "Arirang" Korean. . In 2013, toured a factory called the "May 11 Factory" that makes the "Arirang" . In the August of same year, first Arirang was released and was claimed to the first domestically produced smartphone. . • • • [pdf]
North Korea's government only allows its citizens to use smartphones it created to monitor and control them. While we can't get hold of them here, there's plenty of information available that gives us a fascinating look into the world of North Korean smartphones. Smartphones were introduced to North Korea in 2002, then banned from 2004 to 2008.
The new report catalogs 55 smartphones that have been sold in North Korea, with specifications and other information where available. View and download a copy of the full report at Lumen. In this new report, Martyn Williams examines smartphones, the smartphone market, and wireless networks in North Korea.
One trend noted in recent years is that North Korean smartphone brands appear to have begun offering several versions of a phone with differing specifications. This mirrors the strategy of companies like Apple and Samsung with their flagship products.
These smartphones from North Korea are more than just messaging devices; they act as systems for oversight. Two built-in applications called ‘Red Flag’ and ‘Trace Viewer’ guarantee that the state monitors all device activities. The program Red Flag observes the phone software to stop any illicit changes from happening.
Recent reports say digital payment apps have also been enthusiastically adopted despite their potential for additional surveillance of citizens. One trend noted in recent years is that North Korean smartphone brands appear to have begun offering several versions of a phone with differing specifications.
A glimpse of a North Korean phone with a built-in mosquito repellant. There's also a Google Drive icon that opens a screensaver app. It's hard to confirm these phones' details reliably. Some specifications here are sourced directly from the DPRK state media, so take those with a bucketload of salt.

To calculate the capacitance, we first compute the electric field everywhere. Due to the cylindrical symmetry of the system, we choose our Gaussian. . eq with a total charge Q supplied by the battery. However, since Q is shared by the two capacitors, we must have = Q + Q = C | ∆ V | + C | ∆ V | = ( C . The electric field is non-vanishing only in the region a < r < b . Using Gauss’s law, we obtain JG JG w . A capacitor can be charged by connecting the plates to the terminals of a battery, which are maintained at a potential difference ∆ V called the. [pdf]
As a third example, let’s consider a spherical capacitor which consists of two concentric spherical shells of radii a and b, as shown in Figure 5.2.5. The inner shell has a charge +Q uniformly distributed over its surface, and the outer shell an equal but opposite charge –Q. What is the capacitance of this configuration?
As mentioned earlier capacitance occurs when there is a separation between the two plates. So for constructing a spherical capacitor we take a hollow sphere such that the inner surface is positively charged and the outer surface of the sphere is negatively charged. The inner radius of the sphere is r and the outer radius is given by R.
The equivalent capacitance for a spherical capacitor of inner radius 1r and outer radius r filled with dielectric with dielectric constant It is instructive to check the limit where κ , κ → 1 . In this case, the above expression a force constant k, and another plate held fixed. The system rests on a table top as shown in Figure 5.10.5.
(a) A parallel-plate capacitor consists of two plates of opposite charge with area A separated by distance d. (b) A rolled capacitor has a dielectric material between its two conducting sheets (plates). A system composed of two identical parallel-conducting plates separated by a distance is called a parallel-plate capacitor (Figure 8.2.2 8.2. 2).
Discharging of a capacitor. As mentioned earlier capacitance occurs when there is a separation between the two plates. So for constructing a spherical capacitor we take a hollow sphere such that the inner surface is positively charged and the outer surface of the sphere is negatively charged.
The electric field between the plates of a parallel-plate capacitor To find the capacitance C, we first need to know the electric field between the plates. A real capacitor is finite in size. Thus, the electric field lines at the edge of the plates are not straight lines, and the field is not contained entirely between the plates.

An induction generator or asynchronous generator is a type of (AC) that uses the principles of to produce electric power. Induction generators operate by mechanically turning their rotors faster than synchronous speed. A regular AC induction motor usually can be used as a generator, without any internal modifications. Because they can recover energy with relatively simple controls, induction generators are usefu. [pdf]
Capacitors and inductors are important components in electronic circuits and each of them serve unique functions. Capacitors store energy in an electric field, while inductors store energy in a magnetic field. They have different applications and characteristics, such as energy storage, filtering, and impedance matching.
We opt for inductors over capacitors because inductors hold energy within a field whereas capacitors store energy in a field. Depending on the circuit's needs, like energy storage, filtering or impedance matching an inductor might be a choice, than a capacitor. What is the difference between resistor capacitor and inductor?
The reactive power stored by an inductor or capacitor is supplied back to the source by it. So, since both the inductor and capacitor are storing as well as delivering (releasing) the energy back to the source, why is it said that inductor absorbs reactive power and capacitor delivers reactive power?
Inductors and capacitors both store energy, but in different ways and with different properties. The inductor uses a magnetic field to store energy. When current flows through an inductor, a magnetic field builds up around it, and energy is stored in this field.
Now, observe that SinØ will be negative for Capacitor and hence Q = Negative for Capacitor. Which means that Capacitor is not consuming Reactive Power rather it supplies Reactive Power and hence Generator of Reactive Power. For Inductor, SinØ = Positive, therefore Q = Positive, which implies that an Inductor consumes Reactive Power.
An electric field is produced when voltage is placed across a capacitor's plates, and energy is stored in this field as a result of the separation of charges on the plates. The energy is released when the capacitor discharges, allowing the stored charge to flow through a circuit.
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