Guide Information Blogs

cell phone jammer is to shield the GSM frequency

band, CDMA frequency band and 3G frequency band at the same time.
And broadcasting 24 hours. Fourth, the development prospects of Chinas mobile TV and countermeasures of Chinas mobile TV prospects for the development and Countermeasures 4.1 bottlenecks in the

development of mobile TV to the diverse needs of the audience on the mobile terminal is gradually increasing, making the mobile TV market has shown signs of the trend gaining momentum, the future

can not Limited. Country in the process of development of mobile TV, in some respects, has achieved some success, but also suffered a number of bottlenecks, such as regulatory policy confusion,

lack of communication content, communication technology is lagging behind the lack of professional mobile TV professionals, the use of tariff The high technical standards are not uniform and other

bottlenecks. Regulatory policy confusion. But the area out of the shielding range will not be affected by cell phone jammer .
Management regulations in the telecommunications or radio and television and the management of the mobile TV business clearly defined, the Ministry of Industry and SARFT there mobile TV The

controversy led by whom. In order to capture this emerging mobile TV market high ground, handset manufacturers, telecom operators, radio and television operators have joined the field, the media to

be outdone involved. In accordance with the relevant provisions of the Administration of Radio, all those engaged in online audio and video programs play unit must apply to the Radio and Television

Information Network 09016475 "introduced by the end of 2000, the Telecommunications Ordinance expressly provides image transmission is also a telecommunications areas The former belongs to the

administrative provisions, while the latter is the national laws and regulations. cell phone jammer is developed and manufactured on the basis of the existing product.
The two cross-cutting policies and regulations so that the regulatory policies of the mobile TV 17 confusion. Chaotic regulatory policy also caused a conflict of interest between different

departments, can not reach a consistent understanding of the operating mode of the mobile TV standards, and not within the legal and institutional framework for effective coordination of

broadcasting and telecommunications, and rural development, therefore very make life difficult for the development of mobile TV to create a stable communication environment, hinder the development

process of mobile TV. Secondly, the chaotic regulatory policy to the mobile TV services to carry out the obstacles. For example, some wishing to launch mobile TV service company, to get the mobile

TV business license must apply to the different authorities. cell phone jammer cab be validly used in the prison, detention house, labor camp and so on.The design of cell phone jammer is totally

developed by the nation

With the return of the fine weather, you’ll doubtless be enjoying lazing around of an evening on your patio or in your garden, but even if you’re not surrounded by marshes or other shallow water it’s very likely some intruding mosquitoes will come along to spoil this idyllic scene. Although indoors it’s easy to get rid of them these days, indeed even to prevent them coming into the house, the same can’t be said for the great outdoors.

We might mention the well-known Chinese coils – the only thing Chinese about them is undoubtedly their name – which very often drive people away as much as mosquitoes, if not more! Moreover they are nasty things to handle. There are also UV (ultra-violet) ‘electrocutors’ consisting of a blue lamp surrounded by two closely-spaced grilles between which a high voltage is applied. The mosquitoes (and fies and other flying insects) are supposedly attracted by the color of the lamp and as they approach, get electrocuted in contact with the two grilles.

The only thing you have to do is pull out the drawer from time to time and get rid of the mass of dead insects. Even though the effectiveness of these first two products remains questionable, it is less so than the one we’re nonetheless going to describe here. We’re talking about an ultrasonic mosquito repellent.

The principle, as described by its numerous promoters, is as follows. Only the female mosquitoes bite (that at least is an undisputed scientific fact) and they bite when they need to feed, and above all, to feed their eggs. In this situation, they seek to avoid the males whose ‘job’ has already been done, and so they fy away from the frequencies emitted by the males when they are on heat. This is where opinions now diverge.


According to certain publications, the frequency emitted by the male mosquitoes is said to be around 20–25 kHz, and so within the realm of ultrasound. But according to others, it is in the region of 5–7 kHz instead; frequencies that a human ear, even an elderly one, can still hear very well. Rather than spending lots of money (of the order of tens of pounds) buying such a device, which moreover generally have a fixed frequency, we’re suggesting building one yourself so that you can carry out your own research this summer, especially since the circuit proposed is very simple and cheap to build.

As the figure shows, it uses just a single IC, a CMOS type 4047. This very multi-purpose IC can be wired in very many operating modes, including that of the multivibrator or astable used here. The operating frequency is set by the external components C1, R1, and P1; the latter makes it possible to slightly adjust the frequency, given the uncertainty that exists over the most efective value…To best reproduce the high frequencies produced by the generator, the output transducer used is a simple tweeter, but it must be a piezo one.

Such a tweeter behaves in fact much like a capacitor, and so doesn’t overload the CMOS IC outputs that are incapable of supplying a substantial current, as everyone knows who’s ever worked with 400 series CMOS logic. To obtain an output signal of sufficient amplitude while being powered from a single 9 V battery, this tweeter is connected between the 4047’s Q and Q outputs, making it possible to apply complementary (antiphase) signals to the tweeter so it ‘sees’ an alternating voltage of double the supply voltage.

In purely theoretical terms, this quadruples the output power available. In practice, it’s better to regard it as tripling it, but the beneft achieved by doing it this way is nonetheless very real. All that remains is for you to place the project in the middle of the patio table or beside your lounger in order to get a taste of the calm of a summer’s evening without mosquitoes bothering you acoustically or worse, biting. At any rate, that’s what we wish for you…

A common problem with small torches is the short life-span both of the batteries and the bulb. The average incandescent torch, for instance, consumes around 2 Watts. The LED Torch in Fig. 1 consumes just 24 mW, giving it more than 80 times longer service from 4 AA alkaline batteries (that is, up to one months continuous service). Although the torchs light output is modest, it is nonetheless quite sufficient to illuminate a pathway for walking.

Circuit Diagram :

Fig. 1 : Simple LED Torch Circuit Diagram

The LED Torch is based on a 7555 timer running in astable mode (do not use an ordinary 555). A white LED (Maplin order code NR73) produces 400 mcd light output, which, when focussed, can illuminate objects at 30 metres. Try Conrad Electronic for what appears to be a stronger white LED (order code 15 37 45-11). A convex lens with short focal length is placed in front of the LED to focus the beam. If banding occurs at the beams perimeter, use another very short focal length lens directly in front of the LED to smooth the beam.

If a different supply voltage is preferred, the value of resistor R3 is modified as follows:

9V - 470 Ohm
12V - 560 Ohm

See my "Wind-up Torch" feature article in the October 2000 edition of Everyday Practical Electronics for a completely battery-free go-everywhere torch.