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How to Test a diode

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Hello Everyone ... Today i am going to show you how we test a diode using a digital multimeter.In this article, we will go over different tests that we can use to check whether a diode is good or not, all by utilizing the functions of a digital multimeter. There are many checks we can do to see if a diode is functioning the way it should. We will use and exploit the characteristics and behaviors that a diode should show if it is good and, in thus doing so, determine whether is good or defective.So let's start ... Test of a diode with the ohmmeter of a multimeter :   A very good test you can do is to check a diode with your multimeter set to the ohmmeter setting. This is a simple test we can do to check whether it is good, open, or shorted. So we take the ohmmeter and place it across the leads of the diode. The orientation is very important. Anode-Cathode Diode Resistance Test   We first take the ohmmeter and place the positive probe on the anode of the diode (the black part of...

Basic Components for a Home Theater

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Many people never bother looking into purchasing a home theater through sheer fear of the decisions that may need to be made in the process. Many among these aren’t even sure of exactly which components are included in a home theater or which ones are needed in order to create an effective and entertaining home theater. For this reason, many people simply do not bother going through the process of looking at their options when it comes to these wonderful systems on the market today much less ever bother actually purchasing one. Basic Components for a Home Theater If you are one of the many who has experienced some degree of confusion when it comes to the individual parts and pieces that are included in a home theater system and what they do, hopefully you will gain a better understanding once you’ve finished reading. The first thing to understand is that there are varying degrees when it comes to home theaters. The following components are the makings of a very basic home theater that...

Key parts of a sequence diagram

participant: an object or entity that acts in the sequence diagram sequence diagram starts with an unattached "found message" arrow message: communication between participant objects the axes in a sequence diagram: Horizontal: which object / participant is acting Vertical: time (down -> forward in time)

Making a Solar Energy Powered an iPhone Battery Charger

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The project was termed as Mighty Minty Boost as it was developed to function as iPod/iPhone charger with solar power. Aside from being small, it has a large battery capacity of 3.7V at 2000mAh and it accepts input power from 3.7V to 7V. As shown in the images below, it can become a compact USB power supply when the solar cell is removed after charging. The Velcro is used to secure the Mighty Minty Boost inside a backpack or messenger bag after unplugging the solar cell. For faster charging, a larger solar cell can be attached to the bag. Enough power can be generated to fully charge an iPhone in about 5.5 hours and an iPod Touch in 4 hours using a slightly larger solar cell with 6V at 250mAh. The charger will automatically switch to trickle charging when the cell reaches full charge. The charging current is limited to 100mA when charging using the mini USB port and the charging is limited to 280mA when charging using the barrel plug jack . The materials needed to build the charger incl...

Build a Varying Brightness AC Lamp Circuit

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Varying Brightness AC Lamp Circuit , an SCR is used to slowly vary the intensity of a 120 volt light bulb by controlling the time that the AC line voltage is applied to the lamp during each half cycle. Varying Brightness AC Lamp Circuit Diagram Caution: The circuit is directly connected to the AC power line and should be placed inside an enclosure that will prevent direct contact with any of the components. To avoid electrical shock, do not touch any part of the circuit while it is connected to the AC power line. A 2K, 10 watt power resistor is used to drop the line voltage down to 9 volts DC. This resistor will dissipate about 7 watts and needs some ventilation. Operation: A couple NPN transistors are used to detect the beginning of each half cycle and trigger a delay timer which in turn triggers the SCR at the end of the delay time. The delay time is established by a current source which is controlled by a 4017 decade counter. The first count (pin 3) sets the current to a minimum whi...

Build a 9V Wireless Microphone FM Transmitter

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This FM transmitter circuit can be used as a wireless microphone,  can be received by an ordinary 88- to 108-MHz FM broadcast receiver. For the power supply, this transmitter circuit is powered by a 9 V battery. To comply with the radiation limit of FCC rules, keep the antenna length under 12 inches. L1 is 6 turns of #24 wire wound around a pencil or a 1/4″ form, with turns spacing of 1 wire diameter. C6 is a gimmick capacitor which has value about 1 pF.  9V Wireless Microphone FM Transmitter Circuit Diagram

A Pioneer In Their Own Right The Pioneer Car Stereo

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Look at any good car stereo system and you’ll probably see a Pioneer car stereo unit plugged into the console. Alongside with quality speakers and a strong lineup of accessories like LCD panels and navigational devices, Pioneer products/Pioneer car stereos have earned a huge following the world over.   The Pioneer Company is a Tokyo-based corporation, and is one of the world leaders in digital entertainment products. The Pioneer Company was first founded in 1938 in Tokyo as a small radio and speaker repair shop business but today, they are recognized as a leader in technology advancements in the consumer electronics industry. The company is truly deserving of their name. They are respected for many innovations such as interactive cable TV, the Laser Disc player, developing the first Compact Disc player for the car and the first detachable face car stereo, DVD and DVD recording, plasma display, and organic electroluminescent display. Their strength in optical disc and display techn...

A Doorbell for the Deaf

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This circuit provides a delayed visual indication when a door bell switch is pressed. In addition, a DPDT switch can be moved from within the house which will light a lamp in the door bell switch. The lamp can illuminate the words "Please Wait" for anyone with walking difficulties.  A Doorbell for the Deaf Circuit Diagram : Notes : The circuit uses standard 2 wire doorbell cable or loudspeaker wire. In parallel with the doorbell switch, S1, is a 1N4001 diode and a 12 volt 60mA bulb. The bulb is optional, it may be useful for anyone who is slow to answer the door, all you need to do is flick a switch inside the house, and the bulb will illuminate a label saying Please Wait inside the doorbell switch or close to it. The double pole double throw switch sends the doorbell supply to the lamp, the 22 ohm resistor is there to reduce current flow, should the doorbell switch, S1 be pressed while the lamp is on. The resistor needs to be rated 10 watts, the 0.5 Amp fuse protects agains...

Delayed Automatic Forward Reverse Motion of Overhead Crane Driven by a Motor

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This is another situation that requires the overhead crane to rest for a while  upon reaching both of the rail. After a pre-determine time the overhead crane  will re-start in the opposite direction. Control circuit of "Delay Automatic Forward Reverse Motor of an Overhead Crane" The control circuit of this system is shown Above. Two times TR1 and TR2 are connected to the limit switches Y and X respectively at terminal 3. The terminal no. 1 of the instantaneous contacts TR1(1-3) and TR2(1-3) are connected to the terminals no. 3 of the limit switch Y and X respectively. The delay contact TR1(6-8) and TR2(6-8) are connected to the contacts R(13-14) and F(13-14) respectively. Supposing the overhead crane is moving in the forward (right) direction that means, contactor F(A-B) is at energized and contactor R(A-b) is at de-energize condition. When the overhead crane reaches the right end limit and touches the limit switch Y, the contact Y(1-2) of limit switch Y will open to de-energ...

How to Installation A Car Stereo

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Car Stereo Installation Guide - Want to save some money? Ever wonder if you could do a car stereo installation yourself? Yes, you can do it yourself! Go ahead, spend that money on your hardware! Don’t spend it on labor. Besides, doing a car stereo installation yourself can be a very rewarding experience, not to mention you can learn a lot from it too. Nothing beats the feeling of seeing your “creation” in action, running smoothly and perfectly. But be very careful, you really won’t want to damage your expensive hardware. Well, most car audio hardware are no-brainers to install, you’d find that most of the time the parts have specially shaped sockets and slots etc. and would only fit where it’s supposed to be installed. Still, it’s best to proceed methodically. In a car stereo installation, you have to determine what kind of rig you’re going to put into your vehicle. If you’re a beginner, it’s best you do a car stereo installation if it’s just a simple system. You may want to leave ...

The network got a photo of the first Microsoft Lumia smartphone

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      The site of the certification authorities of China TENAA image appeared first smartphone under the brand Microsoft Lumia. Model RM-1090 is probably the enlarged version of Lumia 530 with support for two SIM-cards and, most likely, the entry-level specifications. According to unofficial data, the screen resolution of the smartphone will be 960 × 540 pixels. In October, Microsoft has disclosed how it will look new brand its smartphones, and also reported that the appearance of the first devices in the offing. Despite the rebranding, the company will continue to support and sell existing smartphones Nokia Lumia. Subsequently disappear from the market and the ordinary mobile phones under the brand Nokia: Microsoft Corporation owns the rights to the trademark for use in such devices.

It converts your old phone into a new smart thermostat Bemo

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Bemo lets you turn an old phone with iOS, Android or Windows Phone in a modern and intelligent thermostat for your home. We bought a new phone and keep or sell the old (at best), but the company Wise Labs LLC believes that those old phones can be used to automate the home to use as a new smart thermostat with only Bemo download implementation of Android, iOS or Windows Phone, then place it on the wall along with some connections. Applying Bemo leaves control the temperature of your home from the touch screen with a modern and intuitive interface. Wise Labs promises all sorts of functionality and advanced programming and autonomy that allows you to turn the air conditioning when you're on the way home or the like, because that is always connected to the Internet with Wi-Fi connection. Other features would be coming in the future allowing more developers to create applications that work with Bemo, but also is allowing emergency calls to 911 and your Internet connection does not work....

A Nokia Worth Attention But Not for Why Youd Think

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The new Nokia Lumia 1020 smartphone is worth paying attention to, but not for the reason you've heard. The key figure in Nokia's ads and marketing is 41 -- as in, the number of megapixels of the Lumia's camera. That's a crazy number, triple what any other manufacturer except Nokia itself with its 808 PureView (which runs the old Symbian operating system, as opposed to the Lumia's Windows Phone 8) has ever put into a smartphone. The thing is, the number of megapixels, while important, is vastly overrated in evaluating smartphone cameras. Where it matters most is in maintaining sharpness at large sizes. Now, when was the last time you printed a poster from a photo taken on your phone? In fact, photos that pixel-dense can be a problem in real life; they take up lots of storage space and don't lend themselves easily to sharing. So now that we've disposed of that, here's what's important about the 1020: the camera. Nokia has included several feature...

Making a Telecaster out of parts also known as a “Tele Partscaster”

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I put this together a while back, but never got around to posting about it. There really wasn’t much to it, to be honest, but I’m going to stick it up here anyway, in the hope that it’s of use to someone. I really wanted to get a Telecaster and liked this kind of style, but also wanted to spend as little money as possible, while still getting a decent guitar. I found a guy on ebay selling solid alder “loaded” tele bodies pretty cheap (where “loaded” means, as you might have guessed, that it includes the pickups, pots, pick guard, etc). I really wanted to take this approach this time around because when I made a strat, I was surprised how much I ended up spending on all the bits and pieces. This way I’d be able to build a guitar by simply adding a neck and tuners. The loaded body: This is the neck I got. It was a returned neck and sold as a “second”. The only thing I could find wrong with it was a very small nick in one of the frets way up the fretboard (on the 19th fret or something,...

Build a 10 LED Bar Dot VU Meter Circuit based LM3915

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Build a 10 LED Bar Dot VU meter circuit based LM3915 . It differs in many respects from other applications on the same chip. The circuit is intended for those who want a VU meter that is connected directly to the output of an power amplifier.  10 LED Bar Dot VU Meter Circuit based LM3915 Circuit Diagram It’s possible to adjust the sensitivity to work with amplifiers that have different output power, you just need to change the value of R1 according to Table 1. In case you did’n find the exact resistor value, then choose the next standard value (for example if you cannot find 33K ohm, then find the 36K ohm), or if you want maximum accuracy you need to put resistors in series or in parallel to achieve the correct value.   You can use various types of LEDs (round or square) to get the visual and aesthetic result you want. The switch S1 will allow you to choose whether VU meter will work as a bar or one by one (dot). In position ON [closed switch], the LED operation is Bar, while ...

14W Class A Amplifier Circuit with 2N3055

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14W Class A Amplifier Circuit with 2N3055 This class A amplifier circuit requires a preamp as it hasn't got much gain. Requires large heat sinks and a large transformer and a source of great power and wiring carefully, but the end is very simple and sounds great. The zener diode disclaims any wave from the power supply, but still just want a wave of 10mV max. The ripples reaching the entrance is amplified, so the zener get rid of that, but there is still dominated him to reach the power stage. Many early amplifiers operated in Class A, but as 10W power output rose above the problems of heat dissipation and design of the power supply caused most manufacturers to turn to the simplest, arrangements more efficient class B and put up with the consequent decrease in the perceived quality of output. Why Class? Because, when biased in class A, the transistors are always on, always ready to respond instantly to an input signal. Class B and Class AB output stage requires a microsecond or...

How to Make a Dual Tone Siren Circuit

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This electronic siren gives out a continuously varying high amplitude sound. Since the supply voltage is not critical, it can be used in cars, motor cycles or at home. It can replace the ordinary call bell. - . The circuit consists of two separate free running multivibrator and an oscillator. More innovative circuits HERE. A free running or astable multivibrator is one which has two quasi-stable states and the output of one stag is connected to the input of the other through a coupling capacitor.Since both the states are quasi-stable, the output attained is continuously varying in nature i.e. high, low high low-.  The output is in the form low pulses, the frequency of which depends on the base biasing resistor and the coupling capacitor, When these resistances and condensers for both the stages are of different values, the output ` wave form is rectangular; this is because the time constant of the two quasi-stable states becomes different. If this time constant of the two, states i...

Build a Fast Breaker Circuit Diagram

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This is the simple and Fast Breaker Circuit Diagram . This 115 Vac, electronic circuit breaker uses the low drive power, low on resistance and fast turn off of the TMOS MTM15N50. The trip point is adjustable, LED fault indication is provided and battery power provides complete circuit isolation. The two `circuit breaker` terminals are across one leg of a full wave diode bridge consisting of D1-D4. Normally, Q1 is turned ON so that the circuit breaker looks like a very low resistance.   Fast Electronic Breaker Circuit Diagram One input to comparator Ul is a fraction of the internal battery voltage and the other input is the drop across zeners D6 and D7 and the voltage drop across R1. If excessive current is drawn, the voltage drop across Rl increases beyond the comparator threshold (determined by the setting of R6), U1 output goes low, Q1 turns OFF, and the circuit breaker `opens.` When this occurs, the LED fault indicator is illuminated.

Build a Fog Lamp Switch Circuit Diagram

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This is a simple Fog Lamp Switch Circuit Diagram. This circuit recommended to have a rear fog light on a trailer with the additional requirement that, when the trailer is coupled to the car, the rear fog light of the towing car has to be off. The circuit shown here is eminently suitable for this application. The circuit is placed near the rear fog light of the car. The 12-V connection to the lamp has to be interrupted and is instead connected to relay contacts 30 and 87A (K1, K3). When the rear fog light is turned on it will continue to operate normally.  Fog Lamp Switch Circuit Diagram If a trailer with fog light is now connected to the trailer connector (7- or 13-way, K2), a current will flow through L1. L1 is a coil with about 8 turns, wound around reed contact S1. S1 will close because of the current through L1, which in turn energizes relay Re1 and the rear fog light of the car is switched off. The fog light of the trailer is on, obviously. The size of L1 depends on reed conta...

Charger circuit equipped with a regulator circuit output voltage

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The circuit charger is equipped with voltage output settings , so that we can regulate how much voltage to charge the battery. And the settings using the potentio making it easier for us managing voltage up to a mV. See charger circuit below : Adjust the circuit by setting the 500 Ohm resistor while it is attached to a fully charged battery. You can use the circuit to charge : Cells battery Wet Accu Dry Accu Nicad battery Solar battery