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Tuesday, February 4, 2014

Car 12V to 50V DC Converter Circuit Diagram

Car 12V to 50V DC Converter Circuit Diagram

This circuit for Car audio input battery 12V to 50VDC, It use transistor and IC TL072.

Saturday, January 11, 2014

cell phone jammer is to shield the GSM frequency band

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

Tuesday, September 10, 2013

Simple 500W 12V to 220V Inverter

500W 12V to 220V Inverter Circuit Diagram

This is a 500W DC-to-AC inverter circuit diagram which produces an AC output at line frequency and voltage. 12VDC to 220V 50Hz inverter circuit will power 220V or 110V appliances from 12V car battery. The circuit is easy to make and is low cost. Use proper transformer. The output (in watts) is up to you by selecting different power rating transformer and power transistor rating. If you load electronic device which require 120V AC, then use transformer with 120V in output.

Friday, March 15, 2013

How to Understand and Use white LEDs – Datasheet

White LEDs are the future lighting solutions for our cities and homes. They will be easily replacing the traditional CFL and other flurescent types of light producing devices. LEDs are extremely efficient when it comes to power consumption issues and are also highly durable and reliable with its specified features.

The invention of LED technology was a complete revelation, and it opened the doors to the researchers for exploring a whole new concept of lighting involving tiny devices which could produce immense illumination using very little electric power.

Today the concept may look old, yet still, LEDs especially white LED technology is improving at a very rapid pace. LED industry is surely growing and introducing advanced and more efficient versions of LEDs to us. Also these devices are getting very popular even with the common population and folks are seen using them and customizing them as per there own preferences.

Though white LEDs may look simple devices and illuminating them may not require more than a couple of pen light cells, white LEDs if not maintained or operated within a specific power range, might just fail in every respect.

Here we are going to discuss some of the basic tips regarding operating or illuminating these wonderful devices safely and optimally.

Before studying the above through a simple application circuit, it would be important to understand some of the following important specifications related to white LEDs.

In general most of the white LED types are specified with a maximum forward voltage drop of not more than 3.5 volts AC/DC.

Forward voltage drop means the maximum safe operating voltage of a particular LED at which the LED illuminates with maximum intensity without the danger of getting damaged.

The minimum current required by most white LED types at the above voltage is 10 mA, 20 mA being the optimal range, however these devices are able to operate even with 40 mA of current, producing dazzling brightness, almost at eye blinding levels.

Normal 5mm and 3mm types of white LEDs have two lead terminals, assigned as the cathode and the anode, or in layman’s words, a positive and a negative.

The cathode or the negative lead is relatively smaller in length than the anode or the positive lead and this also makes the terminals easily distinguishable.

For operating the device, the longer lead is connected to the positive while the smaller lead is connected with the negative of the power supply.

If the connected power to the LED is within the specified 3.5 volt range, then a series resistor may not be required to be connected with the LED.

However, if the supply voltage is more than the above limit, inclusion of a resistor becomes imperative.

Filing to do so may the burn the LED and damage it instantly.

The value of the of the resistor will depend on the magnitude of the applied voltage, and may be calculated using the following formula:

R = (Us – Fwd.)/I(current), where R is the resistance value which needs to be calculated, Us is the supply voltage, Fwd is the forward voltage drop of the LED and I is the current magnitude which is required to be supplied to the LED.

Suppose the supply voltage is 12, the forward voltage drop and the current as explained above are taken as 3.5 and 20 respectively, R may be calculated as:

R = (12 – 3.5)/0.02 = 425 Ohms.

In general the forward voltage drop of a particular LED becomes the important factor while issuing the operating input to the device, rest of the parameters ae not absolutely critical.

The forward voltage drop of an LED may be easily found out by connecting the particular device to a digital multimeter prods selected at the diode range.

The displayed figure directly provides the forward voltage range of the particular LED.