How to Test DC Voltage Regulator IC

It is simple way to test DC voltage regulator. We will test a DC voltage regulator IC, the output voltage level. For example we want to do testing on a 7805 regulator. IC 7805 regulator designed provide a fixed output voltage of 5V, if the good results it will be measured at the pin (3) the amount of output voltage of 5 volts DC.

To perform the test we need a DC power supply panel equipped with a voltmeter, a DC voltmeter, regulator IC 7805 and the black and red wires as needed. Red and black wires are used as a link between positive polarity (+) and negative (-) of the voltage source to the input pin (1) and ground (2) the regulator IC. Output pin (3) and ground (2) of the 7805 IC to be connected to the positive polarity (+) and negative (-) on the voltmeter.

Diagram of DC Voltage Regulator IC Testing

Test DC Voltage Regulator 7805

The things you should know and be prepared prior to testing or measuring voltage regulator is:

• A type of three-terminal regulator IC regulator will work fine if input voltage is greater than the output voltage around 3V. It should be remembered that 7805 was a positive linear type regulator which will be different pinout configurations with IC 7905.
• Turn on the DC power supply and adjust the output voltage of about 8V or slightly larger. Or alternatively you can use a battery 9V-12V as voltage source. Look at the voltmeter panel when you set the voltage
• Prepare a DC voltmeter readings on voltage range 50V to measure the output voltage of the IC 7805.
• Perform the red and black cable connections are correct, red for positive polarity (+) and pin (1) IC, black for polarity (-) and pin (2) IC.

The test results of IC 7805 is good if the pin (3) read positive DC voltage 5V. And you can do it over and over to ensure that the condition of IC 7805 is still functioning well. Do a test for another DC voltage regulator IC..

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How to repair Nokia 5610 keypad fail problem

For nokia 5610 keypad can not function normally

1. Check and clean keypad and doomsheet first

2. If the problem not solved, check flex cable, replace if needed

3. If the problem still not solved , check asip emif keypad and replace if needed.

4. If the problem still not solved, track circuit for broken line.

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How to choose the best for your home theater system

Watching movies is a neat escape from the stressful lifestyle we live in. Watching movies in a wide screen and surround sound take you far away and into the movie scene you are watching. You watch it as if you were there in the movie scene. Of late, we can only experience this escape in a cinema. However, modern technology may be able to provide this same sight and sound experience right in your own living room. We will discuss the basic components of a home theater system in this article. Read on to understand how these basic components can deliver the best cinematic experience to a home theater system.

Home theater experts state that the most important consideration in setting up a home theater system is the size of the room where you will set up the home theater system. The most important component of the home theater system, which is the television, is dependent on the size of the room. Although, the recommendation is 27 inches television set at a minimum is necessary for your home theater set up. It is also a recommendation that a flat television is good for a home theater system because it exhibits fewer glares and produces a crisper image. 

Another major component of a home theater system that depends on the size of the room is the speaker. The number of speakers for your home theater system is dependent on the size of the room. You may add up to six speakers from the basic three speakers if you want a more lifelike sound. Adding a subwoofer may also be good to achieve a complete surround sound like in the movie theaters. Three speakers should be the minimum; you may go up to six if the room is big. 

Another major for your home theater system is the DVD player. It is a recommendation that DVD players with progressive scan will be the best choice. This is because progressive scan produces sharp and flicker-free pictures. This however points back to the choice of television unit; you may need to check if the flat television set supports progressive scan signals. You may also acquire a five-disk carrousel DVD player. This will avoid having to stand up from your seat to change discs every so often. A minor consideration is the power rating that will determine how loud your speaker can be. Of course, almost all these depend on the size of the room to where the home theater system is going to be set up. Small room requires from few types of equipment, bigger rooms may require more and adding home theater furniture to your home theater system may be best. A bigger room thus requires more investments. A smaller room might require fewer but of good quality equipments to avoid the too basic feel of the home theater system.

Finally, you may acquire a beautifully designed home theater system if you consider hiring a home theater expert. If you can afford this, it will be best for you because the home theater expert will be able to effectively design and set up your home theater system. Your home theater designer may also add some features like home theater seating and other home theater furniture to be able to give the complete home theater package that closely resembles a real movie theater. Having the finest and high-quality home theater system will give you the most sought after set up that you could flaunt and enjoy to the max.

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How to Understand and Use High Voltage Transistors BUX 86 and BUX 87

The Bux 86 and BUX 87 are typically high voltage switching transistors with silicon epibase. They come in TO-126 package and are NPN types.

These devices are especially known for their outstanding short switching characteristics and for having a high dielectric strength.

The main applications using these devices can be found with TV circuits, electronic ballasts, converters, SMPS power suppliers etc.

The maximum tolerable electrical parameters for BUX 86 and BUX 87 may be understood with the following points:

Maximum collector to emitter voltage for BUX 86 is 400 volts and 450 Volts for BUX 87.

Maximum tolerable collector current for is 500 mA for both  the devices. 

Maximum tolerable instantaneous peak current across collector and emitter is 1 Amp for <2 ms for both the devices

Maximum tolerable constant base current is 200 mA for both the devices.

Maximum peak instantaneous base tolerable current is 300 mA for both the devices.

 Maximum power dissipation must not exceed 20 watts for both the devices

Typical Static characteristics @ 25 degree ambient temperature of BUX 86 and BUX 87 transistors are listed below:

Collector cut-off current is <0.1 mA

Typical forward current gain for both the devices is around 50

Collector to emitter saturation voltage is less than 1.5 V @ 100 mA collector current and 10 mA base current.

Base to emitter saturation voltage is less than 1 volts @ 200 mA collector current and 20 mA base current.

Maximum frequency handling capacity is 20 MHz for both the devices

Turn ON switching speed is 0.25 micro-second.

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How to Make a Versatile Variable Voltage and Variable Current Power Supply Circuit Using Transistor 2N3055

 A power supply that does not include the features of a variable voltage and current control can by no means be considered truly versatile. A workbench power supply circuit explained in this article is not only specified with a continuously variable voltage control but is also equipped with the feature of overload or continuously variable current control.

A keen look at the circuit design reveals that it’s actually only an ordinary stabilized power supply circuit, however it yet still provides you with the proposed features very efficiently.

The voltage variations are made by using the preset P2, through a feedback configuration employing the components D1, R7, T2 and P2.

The inclusion of D1 makes it sure that the voltage can be lowered right down to 0.6 volts, which happens to be the forward voltage drop of the diode.

If any other specific minimum value is required then the diode can be replaced by zener diode having the required specified value.

Therefore in our circuit, the transformer being a 0 – 40 V, the output becomes variable right from 0.6 to 40 volts maximum, that’s very handy indeed.

For implementing the current control feature, T3 along with P1, R5 and R4 are involved.

The value of R4 is specifically becomes responsible for defining the maximum allowable output current.

P1 is set to choose the maximum range within the value that’s marked or identified by the resistor R4.

Parts List

R1 = 1K,

R2 = 120 Ohms,

R3 = 330 Ohms,

R4 = to be calculated using Ohms law.

R5 = 1K5,

R6 = 5K6,

R7 = 56 Ohms,

R8 = 2K2,

T1 = 2N3055,

T2, T3 = BC547B,

D1 = 1N4007,

D2, D3, D4, D5 = 1N5402,

C1, C2 = 1000uF/50V,

Tr1 = 0 – 40 Volts, 3 Amp

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