Electronic Devices and Circuits

Barang Elektronik Jamanku

2018-11-23T02:36:00.000-08:00

Recognize the Laptop's Hardware

2017-02-28T03:57:00.000-08:00

1. Wifi / WLAN & Bluetooth

Almost all laptop brands now apply a combo module for wifi and bluetooth devices, it means that the two devices are combined in one device. Wifi function to exchange information via hotspot network, while Bluetooth is used to exchange information with other bluetooth devices.

2. Motherboard

Often referred to as the Mainboard. A motherboard or main circuit inside the laptop. In motherboard planted a wide variety of main constituent components that can be turned with a normal laptop. The components include: Processor, Chipset, VGA, Bios, etc. The motherboard is the main engine in the computer.

3. Thermal Module

Most refer to as a fan or a fan. In general, thermal module is divided into two parts, namely: a metal conductor of heat is often called the heatsink or also called heatpipe. While the second part is a fan or a fan that serves to remove the heat out of the laptop.

4. Speaker

Surely already know if that is, that as the audio output on the computer.

5. Hardisk

As a computer user data storage media.

6. Baterai

As a backup power for laptops, so the laptop can be turned without having to connect to the source of electric current.

7. Hinge

If the previously mentioned hinge picture, it was just casing that covers it. The original form of the laptop hinge is as shown above.

8. Memory

If the previously mentioned hinge picture, it was just casing that covers it. The original form of the laptop hinge is as shown above.

MINI PCIE CON FOR WILAN

2017-02-28T03:35:00.001-08:00

Diagram Printer Port

2017-02-28T03:07:00.002-08:00

Wastron Laptop

Blackberry Bold Voltage Point

2013-10-06T10:59:00.000-07:00

Solution Nokia 8910i

2013-10-06T10:44:00.000-07:00

Notebook BOARD and BIOS Chip?

2013-03-30T07:14:00.001-07:00

Blackberry Manual Service

2012-10-16T07:09:00.001-07:00

All Handphone Schematic

2012-09-27T07:37:00.000-07:00

NOKIA N95 HARDWARE REPAIR

2012-06-21T17:57:00.000-07:00

Wireless Resonant Energy Link

2011-08-16T11:17:00.000-07:00

In the experiments have been done by Intel, efficiency has already reached 75 percent. This figure is already very large. However, from the side of the world's energy crisis, the figures were still too small. Intel's research head, Rattner, explaining that the energy wasted is still a big if not done charging. "The level of high efficiency becomes a problem on WREL ( Wireless Resonant Energy Link ), it is almost impossible to be realized."

Levels of efficiency also depends on the alignment of coil and coil wire. When the receiver is rotated slightly, the efficiency decreased dramatically. This is to be avoided by researchers. They replace the coil wires with sensors and microchips that can adjust the resonance in a magnetic field is better

"Electricity could come from the kitchen cupboard," said Justin Rattner. "So, you no longer need to plug the Espresso machine." WREL The transmitter can also be mounted in the wall to supply power to all electronic devices that are in a magical zone. The desk can also be useful to supply and charge the battery all the devices in the vicinity

How to make PCB ( Printed circuit board )

2010-06-23T22:49:00.000-07:00

How to make the following PCB 's experience is the most practical way, besides the cost is cheap, the results are equally interesting and neatly than with how to write directly with a permanent marker, Sablon (Rugos or stencil paint), or media use Transfer Paper (original) the price is quite expensive.
Most people are probably already familiar with this method, but for those who have not used it never hurts to try, especially when the path is now designing the PCB has been very easy to
do with computers.
Materials and equipment that must be prepared are:
1. Laser Jet Printer (Ink Toner) if none can use the Copy results
2. Paper (former) wall calendar that does not wrinkle
3. PCB board
4. Sandpaper smooth paper (abrasive paper)
5. Electric iron
6. Ferri Cloride (FeCl3)
7. PCB Drill
8. Knife (Cutter)
9. Ruler (stainless steel)
10. Permanent markers (if needed)
11. Computers + Software one (TraxMaker, Protel, Eagle, DipTrace, ExpressPCB etc.)

The transfer paths to the PCB board
• Images from the program printed to paper used PCB Calendar (of course the side that are still empty, try the paper calendar is still selected net).
• If the printer toner is not present, then be printed to plain paper and then on Copy
• After a print to paper calendars and ensure that no broken lines, cut out the pictures PCB approximately 2-3mm beyond the line drawings.
• Cut with a knife PCB Cutter PCB size image recently in-print,
align the edge of the PCB until smooth and not sharp.
• Sand the entire surface of the PCB while wetted with water, do the process
sanding by turning it clockwise until clean, then dry.
• Heat Iron, set the thermostat approximately one quarter.
• Position the image above PCB PCB board, PCB line (toner ink) is facing the PCB board (copper).
• Above the calendar paper cover with plain paper, so there in the calendar Text
Iron could not bind to the surface.
• Press the iron is slightly stronger than a thick paper that had been coated with plain paper until about 30 seconds until the picture attached to the PCB board and do the polish evenly to the surface of another.
• The time required during the process of iron + / - 3 minutes, do not let more than
4 minutes, because if too long is usually the picture will be widened / fade.
• After the paper calendar attached to the PCB and PCB board with a way cool
in the wind-wind, never directly immersed into the water or curl with
cold air conditioning, an image (toner) can be peeled off when entered in processes
next.
• If it's really cold, PCB board to soak in water for + / - 15 s / d
30 minutes, depending on the thick / thin paper calendar, until the paper calendar
appear wet on the inner surface, usually if you use paper
thin calendar, paper will peel (floats) on its own.
• Remove the paper calendar slowly by hand until images / lines appear, then gradually clean up the remnants of paper that still sticks with the help of an old toothbrush, especially of paper stuck in the holes / pads between the components and pathways to net.
• If there is an end point, just use permanent marker to cover it.

PCB dissolution process.
• Enter Cloride Ferric (FeCl3) to taste into a plastic container (at least one pack of the packaging), and enter the hot water / warm enough + / - 100ml (half cup), until completely dissolved with water.
• Insert into the PCB board Cloride Ferri solution (FeCl3) before, and so the process is much faster, help with how to rattle the container.
• As observed if the PCB board has been completely dissolved, that is not covered by a copper image / toner, then lift and clean the PCB board with
running water (tap water).
• To clean the image / toners, rubbing sandpaper as he slowly poured the water faucet until completely clean.
• Check again whether there is an end point.
• Drill PCB board according to the foot of the components (0.8 mm up to 1.5 mm)
• Clean the PCB board.
• PCB board ready to be installed components.

Bicycle dynamo powered mobile phone charger

2010-06-10T23:09:00.000-07:00

Cheap mobile phones Nokia launched four new models, and a dynamo powered mobile phone charger homemade bike first, to help protect its dominant market share in emerging markets.

Nokia controls over 50 percent of sales of mobile phones in India and Africa and has strong positions in new markets.

"Tens of millions of these products will be sold, but the competition becomes more intense because the
Chinese vendors aggressively targeting the low cost," said Ben Wood, research director at CCS Insight, told Reuters.

"All the focus on the failure of the smart phone and forget that Nokia is a force in the entry-level product."

Nokia has to compete with other competitors like Apple and RIM in the high-end market, but its failure to offer smart phones have hurt its stock price over the last few months.

Four new mobile phone models sold cheap, are including service and government tax subsidies. Cell phone prices, ranging from 30 euros (36.9 dollars) to 45 euros.

Two new phones with the cheapest price of 30 euros, allows you to use two different SIM cards - to help share the telephone communication between family members or friends.

Nokia also introduced the battery charger (charger) that adopts the workings of a bicycle dynamo is designed for consumers with access to electricity is limited and may be sold for 15 euros, depending on the market, at the end of this year, said a company spokesman.

Charger shaped bicycle dynamo - as a source of electrical power - it can be mounted on bicycle wheels and allows users to charge the phone while driving a mode of transportation at the oars.

Fertility Testing Kits

2010-02-11T06:22:00.000-08:00

You're curious to test the sperm, but ashamed to come to the doctor or lab? In the future, his own sperm test at home is not an impossible thing. The experts in the Netherlands offers a solution by creating a male fertility testing kits that can practically be done at home.

Admittedly, these tools are useful. However, the question arises about the ethical use of the tool if without getting input from the professionals. The reason that the manual counting method is reliable as always accompanied by an expert or a doctor's consultation. It is feared that, without consultation, the tool can actually hurt.

Generally, men slightly embarrassed to check the sperm quality in addition to the procedure, the analysis also takes a long time in the lab. Ejaculate sperm analysis results should begin at the same hour. That is, unless the patient's fertility clinic next door to, he could not prepare the sperm sample from home and must live "produce" in the lab, too. After the samples submitted to the lab, took a long time to perform manual counting method.

"With our system, we can solve the problem," said Segerink.
According to him, his findings chip just need 12 seconds to get the results and the degree of possible error with the manual counting method. Tool that could be used in fertility center hospital, but also can be adapted so that there are variations of a cheap and practical that can be used at home.

On the other hand, Michael Dunn, medical ethics researcher at Oxford University, expressed concern. "There is a risk to the patient if they are not given the relevant information about the impact of positive results sterility," he said.

That is, if it turns out the patient's outcome was barren, she should be given appropriate information so that not one of perception.

Equipment such medical examiners were now needed. Another example is Hywel Morgan and his partners from the University of Southhampton who developed a more practical tool to test viral infection and anemia only from a speck of blood.

"This tool allows the distribution of health services to the public," Morgan said, "However, if you're diagnosing the disease, the results (test of the instrument) must be handled properly

Dinamo 72 Watt Standard

2010-01-31T08:52:00.000-08:00

Dynamo starter had a standard Yamaha Mio 2 ohm loop resistance. In accordance with the size of the wire windings are 0.8 mm. If using 12-volt battery, use power formulas can be known dynamo strength.

From the formula P = V x I've obtained V = 12 volts. Live to find out the price I (amperes). Formula can be found from the voltage V = I x R or I = V / R. R means the resistance of a unit of ohms.

DVB-T Receiver

2010-01-24T04:07:00.000-08:00

The latest development wireless technology has encouraged a change in the entertainment business, one of which is dominated by television. Television broadcast standards will be replaced at least in two years with a new digital television broadcast standard using Digital Video Broadcasting-Terrestrial (DVB-T). DVB-T modulation multiakses using Orthogonal Frequency Division Multiplexing (OFDM) to broadcast the signal through the air as the wireless media.

* EPG (Electronic Program Guide) Ready
* Sub-Title
* Teletext
* Parental Lock
* Favourite Channel List
* Signal Strength Indicator
* Sleep Timer
* OSD Language
* Digital Video Broadcast Teristrial Set Top Box
* EPG (Electronic Program Guide)
* Teletext
* Parental Lock
* Favorite Channel List
* Signal Strength Indicator
* Sleep Timer
* OSD Language (Indonesia / English)
* Video MPEG 2
* Aspect Ratio 4:3/16:9
* AC 220 V
* Power Consumption 6 w
* Frequency Mode 470-862 Mhz
* Bandwidth 8 m
* Demodulator Mode COFDM : 2K/8K
* YUV Output
* Video Output
* Audio Output
* Optical Output

When received at the user acceptance, broadcast signals contain noise caused disability, reflections, etc.. These defects caused a shift in time and frequency signals. OFDM, on the other hand, have excess to compensate for and correct deficiencies by adding a cyclic prefix (CP) in front of each symbol of the signal.

When received at the user acceptance, broadcast signals contain noise caused disability, reflections, etc.. These defects caused a shift in time and frequency signals. OFDM, on the other hand, have excess to compensate for and correct deficiencies by adding a cyclic prefix (CP) in front of each symbol of the signal.

At the receiver, after the antenna and the Analog-to-Digital Converter (ADC), Synchronizer module is required to correct the time and frequency shifts that occur during transmission. This final task is intended to design Synchronizer hardware modules that can be tested and verified using specific models. The results of this final task can be synthesized and integrated into the module DVB-T is greater.

Synchronizer design process is largely based on algorithms from Synchronizer WiMAX has been developed previously. Even so, Synchronizer DVB-T has no frame and the detection can only signify the beginning of the symbol.

The end result of this project is designed Synchronizer still has a little error frequency compensation. Until the end, these errors can still be verified because the reference output can still be improved as a whole. However, the overall function meets the basic objectives of the synchronization algorithm

Personal Digital Assistants

2010-01-19T11:21:00.000-08:00

Personal Digital Assistants PDA is an abbreviated electronic devices and computer-based small form small hand and can be carried everywhere. Inside berbgai also consists of sophisticated features. such as calculators, clocks and time pointer, computer games, The access the Internet, (e-mail), radio, video, and memo recorder, e-books, using the GPS and, internet access, intranet, or extranet via Wi-Fi or Wireless Network . One characteristic of the most important PDA was touch-screen facility.

PDA is different from the communicator. When the PDA tends to widen, the communicator tends lengthwise. Monitor up to three inches in diameter with a touch screen system (touch screens), become one of the typical Personal Digital Assistant (PDA). To operate the PDA, can use the touch screen, stylus or keypad. PDA also has an office application (office rich. Ecxel Applications such as, Word, Powerpoint or PDA Spreadseed buried. Followed with the latest applications, such as document viewer.

PC Development

2010-01-19T10:55:00.000-08:00

Computer users has grown in recent years. In fact, the number of computers currently estimated to have penetrated a 1 billion units.
Calculated according to Gartner analyst institutions. Each year, Gartner predicts the development of the number of PCs in the world reached about 12 percent.
And if these numbers continue, then in the year 2014 the number of PCs is estimated to be spread jumped to 2 billion units. It was a fantastic amount.
Luis Anavitarte, vice president of Gartner said, developing countries will take more roles in the surge of this PC.
"Moreover, governments in many developing countries have committed to minimize the digital divide by promoting more use of PCs to their people, including the layer of lower-class society," he added.
On the one hand, increase in the number of circulating PC can indeed be a positive means of equitable use of technology, but on the other side to consider is the balance of the amount of recycled PCs. Because, if only a waste, electronic equipment is feared will be a waste even be harmful to the environment.
Gartner's own estimates that more than 180 million PCs will be 'removed' owner to be replaced with new ones this year. So you can imagine how much electronic waste that would result if the device is not recycled.

Load Generator

2010-01-17T07:15:00.000-08:00

Electricity as we know it is a secondary form of energy the most practical use by humans, in which electricity is produced from energy conversion processes of primary energy sources such as coal, petroleum, gas, geothermal, water and energy potential of wind.
Power generation systems that have been commonly used is an AC voltage generator engines, where the main mover can type turbine engines, diesel engines or propeller engines. In the operation of power plants with a generator, because the reliability factors and fluctuations in the load, provided two or more generators are operated with constant duty, reserve and turns to these generators.

Provision of a single generator for continuous operation is a risky thing, except when rotating with the source of PLN or UPS equipment.
To meet the increased electrical load generators are operated in parallel between the generator or generators in parallel with other sources of supply for example greater than PLN.
Thus it is also necessary electrical load divider means to prevent any source of electricity generators working primarily parallel experience more burden precedes the other
Generator Operating In Parallel

Electricity supply to the load begins to turn a generator, then gradually added weight to the ability of the generator, then turn on again the next generator and generator memparalelkan the first to bear the burden even greater. When the second generator paralleled with the first generator is expected to bear the burden of sharing the burden borne by the generator which had been the first, resulting in ease of cooperation before the next burdens included.

How big is the load distribution incurred by each generator, which works in parallel will depend on the amount of input fuel and combustion air for diesel engines, when the main diesel engine drive or if the engines driving the other depending on the number (debit) of water into water turbines , the number (enthalpy) of steam / gas to the turbine steam / gas or air flow to the engine propeller.
Number of input fuel / air, water vapor / gas or air flow is controlled by the equipment or the governor-driven valve which receives signals from the change in electrical frequency is stable at 50Hz,
which is equivalent to changing rotation (rpm) engine electric generator prime mover. When electrical load increase the frequency will decrease, so that governors must increase the input (fuel / air, water, steam / gas or air flow) to the main drive engine to increase its frequency until the frequency returned to normal electricity. Conversely if the load down, governor machines should reduce the input power the fuel / air, water, water vapor / gas or air flow to the engines that drive spins down to its normal cycle or frequency returned to normal at 50 Hz. If there is no governor the machine prime mover overspeed generator will experience a sudden fall when the load or will experience electrical overload when the load increases.

Principle Tool Generator Load Dividers

Governor operate on machines that drive generators to produce output currents can be adjusted from 0% to 100% capacity. So the input to the engine output drive current is proportional to the generator or in other words the governor setting to 0% to 100% proportional to the flow generator with a 0% to 100% in voltage and constant frequency.
Governor hydraulic work / mechanical, while the input signal from the output of the electrical current generator, so that this input should be changed to using elektric mechanical actuators to move the electric motors that produce mechanical motion required by the governor.

In some generators that operate in parallel, as previously identified voltage, frequency, and sequence phasa different phasanya, changes in electrical load will not be felt by each generator in the amount of voltage and frequency for the load is still below the total capacity of the parallel, so that the voltage and frequency is not used as a signal source for the governor.

Was used for the current output of each signal generator as a source of burden sharing parallel system such generators.
When paralleled generators burden sharing has not balanced / proportional to the ability of each generator. Load generator tool distributor is attached to each generator output circuit, and each distributor load devices are connected in parallel with the next one with a cable to add signal output current of each generator and the summing signal flow capacity of each generator.

Generator output current detected by means of dividing the load will be the governor's position clue how%, or currents through what% of generator capacity. Results for the sum of the currents detected by means of dividing the load by the number of current generators the ability to operate in parallel multiplied by 100 (%) is the governor's position value to be achieved by each prime mover engine that produces output currents proprosional and in accordance with their capabilities each generator.

If the size of the generator as the amount of current detected by each instrument load divider is divided by the number of generator load current that must be produced by a generator after governornya modified by the electric actuator that receives signals from the instrument as soon as the quota burden paralleled generators.

Technical Installation

In practice the load divider tool fitted with the help of generator components such as the following: current transformer, voltage transformer (as the power supply), electric actuators, speed control potentiometer and switches help. See pengkabelannya diagram in Figure 1.
1. Current transformer transducer functions as a generator output current to flow for the appropriate signal to the load generator tool distributor (usually a maximum of 5 A or 100% = maximum generator capacity)
2. Voltage transformer serves as a resource for the load divider tool, generally with a voltage 110 V AC, 50 Hz; assisted adapter for DC voltage.
3. Electric actuators are devices that receive signals from the load distributor means so as to move the DC motors in the governor until the generator output current reaches the expected.
4. Speed control potentiometer is a primary tool to regulate the frequency and voltage when the generator will be parallel or in the process of synchronization. Voltage is generally set by the AVR, so that the voltage fluctuation is only influenced by the mover engine rotational speed. After the generator is operated paralelkan or already in sync with what has been in operation and closed MCCB generator, speed control potentiometer function was taken over by means of dividing the load generator. To more accurately setting the synchronization speed in the process manually, there is usually a potentiometer and the potentiometer regulating regulator smooth rough.
5. In the automatic control system pemaralelan generators can be made by SPM (pemaralel generator module) by regulating voltage and frequency output of the generator, and then match the voltage and frequency with which the system is working automatically, after the match to give closure to the MCCB signal generator so that the join in parallel operation . To match the voltage and frequency can be seen in one panel is used with synchronous for some generators where each generator has a switch panel as well synchronized his SPM.

In Figure 2 indicated the use of a generator load divider in a control system of power generators, machine controls and management burden activator. (File power generation control).
f. The switches help to divide the load generator tool serves as a manual distribution process (release & capture) load by a generator which operates in parallel systems. For example, * the switch 1 is closed to minimize the diesel fuel that is released .* burden to switch into 3 covered in class speed (rated speed) which means taking the load from the generator to the electrical load lightened.
After the generators operate in parallel, generators with a load divider always responded actively raising any action or decrease in electrical load, so that each generator bear the burden with the same percentage measured by the ability of each
Conclusion

1. Load generator tool distributor is a uniform automated equipment operations in the governor power to raise or lower the engine or generator power according to load changes, and very necessary if you have more than two generators with different characteristics that operate in parallel.
2. By means of dividing the load generators, each generator has a usage factor (divided by the maximum load capacity of the generator) the same and small, which means good.
3. Load changes due to income or expenditure of the parallel system generator generators will be felt equally by each generator in the system they will, without overload or overspeed.
4. Load generator tool distributors can only be applied to the engine generator-set that has the governor and could be developed for control systems such further control by a distributed control system (DCS)

PS3 Slim

2010-01-04T10:08:00.000-08:00

PS3 Slim is one of the Sony effort to reduce the size and cost of the PS3 original. But now it seems Sony was thinking to innovate further.

Masayuki Chatani, from the Sony Computer Entertaiment said that they plan to further decrease the longer version of the PS3 Slim, not only that, Masayuki said that they were also looking for a solution to the problem size HDD. One alternative is to use "flash memory" in the PS3, which in addition to reducing the size, also can reduce the "noise level" in the console

Meanwhile, the other alternative is to use the PlayStation Network to save game data fully, personal files and settings. A bit similar to how Gmail. Unfortunately, according to Masayuki, after further thought both those options would make the price too high compared to the PS3 storage needs, hence they planned to continue using the HDD as usual.

Masayuki also said, that when compared with the PS2 Slim, is far smaller than the PS2 original, it allows for more down the size of the PS3 Slim, but to do so, Power Supply console should be placed on the outside, like PS2 Slim, where it This will be a little difficult if you want to shift the console.

Playstation 3 (PS3)

2010-01-03T10:10:00.000-08:00

Sony Computer Entertainment America (SCEA), Inc.. today announced the launch of new models of Playstation 3 (PS3), the 80 GB model. Starting this August, the new PS3 model will be sold in America with a retail price of $ 599, and will sell a package with a car racing game MotorStorm title was given the ability to play online.

With features hard disk drive (HDD) is expanded, 80 GB PS3 is designed to attract the interest of online gamers and fans of digital entertainment world, which will provide greater space to download more games or to store content downloaded from the Playstation Network . MotorStorm given in this package allows 80 GB of 12 players to play online at once, in a car racing game on the ground with visuals extraordinary.

Both PS3 models have Cell Broadband Engine (TM) (Cell / BE), Blu-ray Disc (TM) (BD) player, an integrated HDD in it, 1080p
high-definition output, Wi-Fi connection, and the SIXAXIS wireless controller (TM).

Electronic Waste

2010-01-02T22:33:00.001-08:00

People today are familiar with the changing habits of electronic goods such as computers, hp, laptops, television, or radio. But has it ever crossed our minds, would where secondhand goods that we remove it?

Electronic Computer

2009-10-08T04:22:00.000-07:00

Guiyu cities in mainland China is home to a cottage industry of 5500 to process the parts of the electronics used, known as e-waste (electronic waste). Based on data from local sites, the region annually process around 1.5 million pounds of waste consisting of waste computers, mobile phones and other electronic devices. The industry became a lucrative job opportunities for people in Guiyu.

Most mobile phones and old computer equipment can be dismantled and the metal components in it is recycled, but the running of this recycling process is safe requires a very long time.
Therefore many electronics manufacturers are sending out electronic former country, where These tools were burned regardless of Environmental and human health in the vicinity.

Almost 80% of discarded electronic equipment is processed comes from outside China, particularly fromAmerica, the only industrial country that refused to sign the Basel treaty designed to regulate hazardous waste exports to developing countries for recycling.

They chose an electronic trash in Guiyu and other similar places in India and the region Africa, because the cost is cheaper and easier mechanism, where the company is not bound recycling regulations are strict. Of electronic waste processing business, the site Guiyu reported annual revenue of about 75 million dollars.

They are processing electronic waste by separating each section and group them, then
retrieve content of tin, gold, copper and other metals from circuit boards, cables, chips and Another part of the electronic device. In the photo on a worker was heating board computers on the metal layer to strip tin solderan of computer chips.

This small industry employing 10,000 people mostly under-age. Imaginable
result of electronic components that contain mercury and toxins harmful to them.
Medical reports from the area mentioned Guiyu many children who suffer because of the high levels of environmental pollution due to lead. Later reports from Shantou University, Guiyu have high levels of cancer patients caused by the dioxins highest in the world and the increase in cases of miscarriage in pregnant women.

These industries produce a lot of environmental pollution because of waste processed, especially dust from burning coal is directly discharged into rivers and sewers of the city, causing pollution of water wells and ground water.

Seeing the pictures above we may be more sensible and wise in buying and using electronics products, buy that suit their needs and also consider the age of use, which can reduce the volume of waste generated. Purchased products only from manufacturers that produce environmentally friendly products

a Fire Alarm Circuit

2009-10-07T23:07:00.001-07:00

When a fire broke out at room temperature increases. It is very compact and low cost fire alarm senses fire based on this fact.
BC177 transistor (Q1) is used as a sensor fire here. As the temperature increases transistor leakage current is also increased. This circuit is designed so that when there is increased leakage currents Q1, transistor Q2 will be biased. As a result there is a fire escape when the transistor Q2 will be in. The emitter of Q2 (BC 108) is connected to the base Q3 (AC 128). Thus, when Q2 is ON Q3 will also be ON. Q3 relay drive transistors used to drive the load ie, lights, bells, horns, etc. as an indication of the fire. Diode D1 is used as a diode to encourage free to protect her from the back EMF generated when the relay is activated.

Circuit diagram with Parts list.

Note.

* The preset R1 can be used for the desired temperature level to set the alarm ON.
* This is not an alarm attached, ie: when the temperature around the sensor decreases below the set point the alarm stops.
* The circuit can be supported by using 9V battery or 9V battery eliminator.
* All electrolytic capacitors and must be given a minimum value of 10V.
* Load can be connected through C, NC, NO points of the relay according to your needs.
* The calibration can be done by using soldering iron, and thermo-meter. Switch ON the power soldering iron tip supply.Keep near Q1. The same time keep the thermometer close to it. When the temperature reaches the desired value to adjust R1 so that you will relay ON

Variable DC Power Supply

2009-10-06T18:19:00.000-07:00

Voltage range: 0.7 - 24V
Current limiting range: 50mA - 2A

Parts:

P1____________500R Linear Potentiometer
P2_____________10K Log. Potentiometer

R1,R2___________2K2 1/2W Resistors
R3____________330R 1/4W Resistor
R4____________150R 1/4W Resistor
R5______________1R 5W Resistor

C1___________3300µF 35V Electrolytic Capacitor (see Notes)
C2______________1µF 63V Polyester Capacitor

D1,D2________1N5402 200V 3A Diodes
D3_____________5mm. Red LED

Q1____________BC182 50V 100mA NPN Transistor
Q2____________BD139 80V 1.5A NPN Transistor
Q3____________BC212 50V 100mA PNP Transistor
Q4 __________2N3055 60V 15A NPN Transistor

T1_____________220V Primary, 36V Center-tapped Secondary
50VA Mains transformer (see Notes)

PL1____________Male Mains plug

SW1____________SPST Mains switch

Device purpose:

A Variable DC Power Supply is one of the most useful tools on the electronics hobbyist’s workbench. This circuit is not an absolute novelty, but it is simple, reliable, “rugged” and short-proof, featuring variable voltage up to 24V and variable current limiting up to 2A. Well suited to supply the circuits shown in this website. You can adapt it to your own requirements as explained in the notes below.
Notes:

* P1 sets the maximum output current you want to be delivered by the power supply at a given output voltage.
* P2 sets the output voltage and must be a logarithmic taper type, in order to obtain a more linear scale voltage indication.
* You can choose the Transformer on the grounds of maximum voltage and current output needed. Best choices are: 36, 40 or 48V center-tapped and 50, 75, 80 or 100VA.
* Capacitor C1 can be 2200 to 6800µF, 35 to 50V.
* Q4 must be mounted on a good heatsink in order to withstand sustained output short-circuit. In some cases the rear panel of the metal box in which you will enclose the circuit can do the job.
* The 2N3055 transistor (Q4) can be replaced with the slightly less powerful TIP3055 type.