Tuesday, February 4, 2014

USB Sound Card

In this article I will discuss my own experiences about designing a USB sound card, which is the USBDAC. DAC is an acronym for Digital-to-Analog Converter because in a sound card, digital data representing the sound is converted into analog voltage that moves the speaker cone.

 Designing a USB Sound Card

My device is loosely based on the PCM2706 reference design. I will not go through the tecnical details but instead concentrate on my own experiences in the design of the device. This is to keep people not familiar with electronics, as well as newcomers to electronics design, interested. You will see that one working product is the result of many failed prototypes. 
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Friday, January 10, 2014

The multi laser Cell Phone Jammers will have more functions

 The multi-laser Cell Phone Jammers will have more functions.
In order to make a variety of data and processing rate of more stringent requirements, these should be recorded and analyzed sound and light signals, and converts it into control signals back to the feedback loop to drive an electromechanical device, the laser welding systems, weld and compensation joint defects. Laser welding, there are two basic ways: conduction welding with deep penetration (holes) welding. Both ways the most fundamental difference is: the former pool surface remain closed, while the latter was the laser beam penetrates into the pool hole. Conduction welding small perturbation of the system, because the laser beam of radiation does not penetrate the welded materials, therefore, in the process of conduction welding seam gas can not easily be penetrated; and deep penetration, the holes can lead to continued close pores. Conduction mode welding and deep penetration welding can also be in the same process of conversion by conduction to the hole pattern is applied to the workpiece depends on the peak laser power density and laser pulse duration. Laser pulse energy density of the laser welding can be time-dependent laser material interaction during welding by a shift to another way that the interaction process in the weld can be formed in the conduction mode, then change way for the hole. The RF remote of Cell Phone Jammers is embedded with the wireless RF emitter of Cell Phone Jammers . After the reunification of students in the comparison of light painting. Conclusion: The beam shines on opaque objects, reflections occur at the interface; Conclusion: beam shines on opaque objects, reflections occur at the interface; the light shines on a transparent object is refracted at the interface. The object is refracted at the interface. ③ medium: light in the air, water, glass and other transparent material in the spread of these substances is called the medium: the light in the air, glass and other transparent material in the spread of the light medium. Optical media.What is the form of the light spot of a  Cell Phone Jammers ? Light in the same medium must be along a straight line it? Teacher demonstration experiments: light in the same medium must be along a straight line it?The above mentioned example, laser processing equipment is made entirely of industrial lasers and laser processing systems and processes are implemented. Shows the domestic laser processing equipment has been in many industrial processes to meet the requirements of the import price than cheap laser processing machine several times, and maintenance services with timely, easy replacement of wearing parts and spare parts to the original and easy. Laser processing major applications in the electronics, automotive, machinery, iron and steel metallurgy, petroleum, light industry, medical equipment, packaging, gift industry, and so on, and increasingly expanding range of applications, from its annual sales growth can be seen that . On the basis of the foreign market seminar laser processing statistics, the output value of nearly four years are listed below (Table 1): As can be seen from Table 1, the laser processing system with an average annual sales growth rate of 13%.
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Simple Dual 50V 5A Universal Power Supply Circuit Diagram

This is the simple Dual 50V/5A Universal Power Supply Circuit Diagram. Tl has two primaries and six secondaries; the two 120-VAC primaries and 6.3-VAC secondaries are in parallel. Modules A and are identical; hence, only Module A`s parts are called out. Module C is wired point-to-point on the IC3 heat-sink.

Dual 50V/5A Universal Power Supply Circuit Diagram

Dual 50V/5A Universal Power Supply Circuit Diagram

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Thursday, January 9, 2014

I dont think any of us want to see that happen

 I dont

think any of us want to see that happen!
When you need to make cell phone calls, you should find an isolated place to do it. In the break room during lunch when there are twenty other employees sitting around is not a private place.

Having a conversation in front of your co-workers that they are not included in is rude. If you chose a place out in the work place during your break time, it may distract the people who are still

working as they try to overhear your conversation.
You should never ever use your phone in the public restroom. If one of your co-workers is going to the bathroom and the person on the other end of your call can hear them that is an invasion of

your coworkers privacy. You might also consider that many bathrooms in the work place are large and echo so that any co-worker who is present may be able to hear the entire conversation.
You should not bring your cell phone to any meetings. Your concentration should be on your job and your boss will notice if you are paying attention. Even if you have your cell phone set on

vibrate, if it rings it can disrupt the entire meeting as well as gain you some unwelcomed attention by your supervisor. You should also never check your cell phone to identify who is calling.How can one complain about

technology that does that? The benefit of this technology should be to free up time, assured that no call will go unreceived, and all calls can be returned at the most convenient time. But, rather

than turn off the phones when occupied, people keep them on at all times.
Unfortunately, no landfill is 100% safe and it is the toxins that leach from these materials into the ground which pollutes our water table and our drinkable water supply. Currently less than 1% of

the entire earths water is drinkable so we must take steps to protect it.
Studies from the University of Northwest Indiana have revealed that a whopping 82% of landfills in Northwest Indiana alone experienced leaks, a frightening statistic when you consider how much harm

it poses to the surrounding environment and that the effects such as migration of methane gas and leaching contaminants cannot be isolated.
So toxic are the emissions from landfills that living within a close proximity of one can affect health such as low birth weight in newborns, shorter height than the general population and heart

defects and liver abnormalities to name a few. If these are just some of the side effects from landfills, imagine what we are throwing into them.
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It can be used by the customer to remotely control cell phone jammer

It can be used by the customer to remotely control cell phone jammer
Relatively more advanced exploration of the United States in this regard: "God blind date in mind," the first micro-funny drama is taken by the United States for the mobile video, the entire film is only two minutes long, this story is absurd comedy drama is the middle of the hundreds of thousands of mobile phone users in Europe and America spread; Fox Following the successful launch of a thrilling counter-terrorism TV series "24 hours" [2] and the UKs largest mobile company Vodafone Cooperation, launched at the end of 2004, the mobile phone version of "conspiracy", episode 1 minutes, a total of 24 episodes in 23 countries launched simultaneously with the TV version of "24 hours"; U.S. producers of the ABC television network announced to the specialized production of a mobile phone version of "Lost", a total of 20 episodes, each episode is only a few minutes, a file to the TV for the pilot and main carriers downright cross-media programs. The site environment will affect the production process of high tech cell phone jammer .
If the customer does not choose monthly unlimited, in accordance with pay-per-view for billing purposes. Rate information of the section program introduced in the program below. The pay-per-strategy as follows: Customer demand / download the same program, only charge a pay-per-cost of re-use within 72 hours. Information fee free business: mobile video service to provide users with some free programs and users to watch programs without paying the fee information. If the customer can watch for free mobile video free zone "program. Off-site roaming mobile video business fee tariff and watch mobile video services in the local rates are the same. EGPRS network coverage area or TD-SCDMA network coverage area the mobile video business will not be an additional charge.  In addition to the use of pay-per-mobile advertising model should also be taken into account, provided there is sufficient amount of user and product viscosity advertising advantages that can reduce the complaints to improve the product viscosity can also bring new profit growth point. The user experience to improve the user experience the sense of the experience, improve the user experience, we must first understand what the target population of mobile video. The site environment of the area where cell phone jammer will be manufactured and assembled is very important.
While mobile video can be downloaded directly through the mobile network due to network speed is too slow, the user will select a variety of ways for the transmission of video files. The research shows that the proportion of users downloaded via computer and mobile phone web site to download close to 28.5% and 27.5%, respectively. Internet video phone download function had a great impact on the user, but use only accounted for 20.6% (see Chart 3). This shows that the user can watch the video on the Internet, are not very willing to download the video again to your phone.
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Thursday, December 26, 2013

V Charger Circuit Diagram

The charger is based on a charging voltage of 2.4 V per cell, in accordance with most manufacturers recommendations. The circuit pulses the battery under charge with 14.4 V (6 cells ? 2.4 V per cell) at a rate of 120 Hz. The design provides current limiting to protect the chargers internal components while limiting the charging rate to prevent damaging severely discharged lead-acid batteries. 

The maximum recommended charging current is normally about one-fourth the ampere-hour rating of the battery. For example, the maximum charging current for an average 44 ampere-hour battery is 11 A. If the impedance of the load requires a charging current greater than the 11 A current limit, the circuit will go into current limiting. The amplitude of the charging pulses is controlled to maintain a maximum peak charging current of 11 A (8 A average).

V Charger Circuit Diagram

V Charger Circuit Diagram

V Charger Circuit Diagram
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Tuesday, December 24, 2013

LM4990 2 Watt Audio Power Amplifier with Selectable Shutdown Logic Level

The LM4990 is an audio power amplifier primarily designed for demanding applications in mobile phones and other portable communication device applications. It is capable of delivering 1.25 watts of continuous average power to an 8Ω BTL load and 2 watts of continuous average power (LD and MH only) to a 4Ω BTL load with less than 1% distortion (THD+N+N) from a 5VDC power supply. Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. The LM4990 does not require output coupling capacitors or bootstrap capacitors, and therefore is ideally suited for mobile phone and other low voltage applications where minimal power consumption is a primary requirement.



2 Watt Audio Power Amplifier with Selectable Shutdown Logic Level  2 Watt Audio Power Amplifier with Selectable Shutdown Logic Level

The LM4990 features a low-power consumption shutdown mode. To facilitate this, Shutdown may be enabled by either logic high or low depending on mode selection. Driving the shutdown mode pin either high or low enables the shutdown pin to be driven in a likewise manner to enable shutdown. The LM4990 contains advanced pop & click circuitry which eliminates noise which would otherwise occur during turn-on and turn-off transitions. The LM4990 is unity-gain stable and can be configured by external gain-setting resistors.
 Features

  • Available in space-saving packages: LLP, Exposed-DAP TSSOP, MSOP, and ITL
  • Ultra low current shutdown mode
  • Improved pop & click circuitry eliminates noise during turn-on and turn-off transitions
  • 2.2 - 5.5V operation
  • No output coupling capacitors, snubber networks or bootstrap capacitors required
  • Unity-gain stable
  • External gain configuration capability

  • User selectable shutdown High or Low logic Level
    Key Specification
    Improved PSRR at 217Hz & 1KHz  62dB
    Power Output at 5.0V, 1% THD+N, 4Ω (LD and MH only) 2W (typ)
    Power Output at 5.0V, 1% THD+N, 8Ω 1.25W (typ)
    Power Output at 3.0V, 1% THD+N, 4Ω 600mW (typ)
    Power Output at 3.0V, 1% THD+N, 8Ω 425mW (typ)
    Shutdown Current 0.1µA (typ)

    Applications

    • Mobile Phones
    • PDAs
    • Portable electronic devices
    Datasheets

    Source: http://www.ecircuitslab.com/2011/07/lm4990-2-watt-audio-power-amplifier.html

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