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Saturday, January 11, 2014

Under this circumstance cell phone jammer should be packed well

 Under this circumstance, cell phone jammer should be packed well. 
In 1999, the Groups industrial sales revenue of 21.5 billion yuan. In August 1997, Haier was the State Economic and Trade Commission identified as one of the six first technological innovation pilot enterprises, focusing on supporting the impact of the worlds top 500. "Difficult first" strategy, insist on playing the Haier brand exports, Haier is now 62 dealers in overseas development, more than 36,000 distribution points, products exported to the worlds top ten economic regions in Europe, America, Middle East, Southeast Asia 90 countries and regions, 1999, Haier brand export $ 138 million. Has five factories overseas, in the construction of eight, toward the the goal of the internationalization of enterprises. In April 1999, the trinity of Haier was set up on the road of internationalization, Haier has taken a solid step forward. Actually, the inspection process of the raw material of cell phone jammer is the vital and complicated process.
In 1997, the United States "appliance" magazine published the worldwide fastest growing home appliance business, Haier than GE, Siemens and other world famous, top of the list. March 25, 1998, Haier Group CEO Zhang was invited to board the Harvard University forum, "Haier culture activate the shock fish" cases formally written into the Harvard University teaching materials, marking Haier real to the world. November 30, 1998, the British "Financial Times" reported: in the companies rating the reputation of the Asia-Pacific region, Haier ranked seventh, is the only top ten Chinese enterprises. In 1999, the U.S. magazine "Fortune" to "the power of Chinas Haier much coverage of the results obtained by the title of the Haier Group. The inspector should check the rigidness, appropriateness of the raw material of cell phone jammer .This kind of design of cell phone jammer is the systematic study on the above problems
99 Fortune Forum in Shanghai conference Haier Group Zhang president as the sole participation of a Chinese home appliance entrepreneurs and make a speech. December 7, 1999, the British "Financial Times" published the worlds 30 most respected entrepreneurs ranking Haier CEO Zhang Ruimin Rong, ranked 26, which is the highest reputation of Chinese entrepreneurs worldwide. To speed up the enterprises to enter the worlds top 500 pace, the completion of the Haier "three parks, one school", the three parks Haier Development Zone Industrial Park, Haier Information Park, Haier Park, a school Haier University Department. June 25, 1999, the General Secretary Jiang Zemin visited Haier, when listening to Zhang reported by the President of Haiers goal is to enter the worlds top 500, said happily: "I look completely. The manufacture process of cell phone jammer should also be strictly controlled.
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Friday, January 10, 2014

25 Metres Range Short Wave AM Transmitter


Here the short wave AM Transmitter circuit design diagram. The circuit is quite simple and easy to build since it applies only a few electronic components. The primary feature of this transmitter is that it really is absolutely free from the LC (inductor, capacitor) tuned circuit and runs using a fixed frequency of 12 MHz that is very stable. An LC based tuned circuit is inherently unstable because of drift of resonant frequency due to temperature and humidity variations.

25 Metres Range, Short Wave AM Transmitter Circuit diagram :



Resistors R1 and R2 are utilized for DC biasing of transistor T1. The capacitor C1 gives coupling in between the condenser microphone and the base of transistor T1. In the same way, resistors R3, R4 and R5 give DC biasing to transistor T2.

The oscillator segment is a combination of transistor T2, crystal XTAL, capacitor C2, C3 and resistors R3, R4 and R5. The crystal is excited by a portion of energy from the collector of transistor T2 via the feedback capacitor C2. The crystal vibrates at its essential frequency and the oscillations happening because of the crystal are placed to the base of transistor T2 across resistor R4. Using this method, continuous undamped oscillations are acquired. Any crystal having the frequency in short wave range could be substituted in this circuit, even though the operation was tried using a 12 MHz crystal.

The Transistor T1 has 3 capabilities:
  1. The transistor features the DC path for extending +VCC source to transistor T2.
  2. It amplifies the audio signals which is generated by condenser mic.
  3. It injects the audio signal into the high frequency carrier signal for modulation.
The condenser microphone transforms the voice message into the electrical signal that is amplified by transistor T1. This amplified audio signal modulates the carrier frequency produced by transistor T2. The amplitude modulated output is acquired at the collector of transistor T2 and is transmitted by a loop antenna into space in the form of electromagnetic waves. The antenna could be tuned to a specific frequency by fine-tuning the trimmer C5 and also by modifying the length of ferrite rod into the coil.

The transmitted signals could be received on any short wave receiver without having distortion and noise. The range of this transmitter is 25 to 30 metres and may be expanded even more in case the length of the antenna wire is suitably extended together with good matching.
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Simple Unipolar to Dual Supply Converter Circuit Diagram

Simple Unipolar to Dual Supply Converter Circuit Diagram. 817V The outputs in this circuit are independently variable and can be loaded unsymmetrically. The output voltage remains constant, irrespective of load and changes. By varying potentiometers R2 or R6, the output voltages can be conveniently set. Outputs can be varied between 8 and 17 V, so that the standard ±9, ±12, and ±15 V settings can be made. 

Unipolar to Dual Supply Converter Circuit Diagram

Unipolar to Dual Supply Converter Circuit Diagram


This converter is designed for a maximum load current of 1 A and the output impedance of both supplies of 0.35 0. This circuit is not protected against shortcircuits, but uses the protection provided by the de input source. This circuit is ideal for biassing operation amplifier circuits.
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