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

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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

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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Simple Digital Switching System

This circuit can control any one out of 16 devices with the help of two push-to-on switches. An up/down counter acts as a master-controller for the system. A visual indication in the form of LEDs is also available.  IC1 (74LS193) is a presettable up/ down counter. IC2 and IC3 (74LS154) (1of 16 decoder/demultiplexer) perform different functions, i.e. IC2 is used to indicate the channel number while IC3 switches on the selected channel.

Digital Switching System Circuit Diagram :

Before using the circuit, press switch S1 to reset the circuit. Now the circuit is ready to receive the input clock. By pressing pressing switch S2 once, the counter advances by one count. Thus, each pressing of switch S2 enables the counter to advance by one count. Likewise, by pressing switch S3 the counter counts downwards.

The counter provides BCD output. This BCD output is used as address input for IC2 and IC3 to switch one (desired channel) out of sixteen channels by turning on the appropriate triac and the corresponding LED to indicate the selected channel.  The outputs of IC3 are passed through inverter gates (IC4 through IC6) because IC3 provides negative going pulses while for driving the triacs we need positive-going pulses. The high output of inverter gates turn on the npn transistors to drive the triacs. Diodes connected in series with triac gates serve to provide unidirectional current for the gate-drive.

Sorce : www.ecircuitslab.com/2012/08/digital-switching-system.html

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Fox Hunt Transmitter

This 2 meter 144 MHz fox hunt transmitter is used in amateur competitions where a hidden transmitter is to be “hunted” using mostly home brewed receivers and antennas. The foxhunt electronic circuit is the transmitter. It radiates a high quality signal without unwanted harmonics. Transistor T1 and the crystal together make the oscillator that generates a 36MHz signal.

The unwanted 12MHz basic frequency of the oscillator is suppressed by the filter circuit made of L1, C3, C2. The L2/C4 circuit is set to the fourth harmonic or 144 MHz. The signal goes to the dual-gate-FET driver stage before finally radiating through the transmitting antenna. The output power is from 10…40mW. The radiated signal is also modulated by the gate circuit made of U1, U2, U3, U4. Gate U1 is a low frequency oscillator which generates a signal from 0.1 to 0.5Hz. This signal modulates the transmitter through the transistor T3.

Fox Hunt Transmitter Circuit diagram

If the U1 output is “0″, transistor T3 is off and the transmitter is also off. On the other hand, if the U1 output is “1″, transistor T3 is on and the transmitter is on. During the “1″ period, gate U2 generates a square wave signal with a frequency form 0.1 to 1Hz. Gate U3 works as an inverter only. It determines whether gate U4 generates a 1KHz signal or not. A periodic burst signal is now present at the gate FET T2 to modulate the transmitter used at foxhunt.

Calibration of the foxhunt transmitter: Adjust the three trimmer capacitors to produse a maximum signal amplitude at the output.
Coil data:
L1 = 470 nH
L2 is made of 5 windings of 0.8mm copper wire, 8 mm winding diameter. It is tapped at the first winding from the ground.
L3 is made of 0.8mm copper wire, 8mm winding diameter, 3 windings at the FET side and 2 windings at the antenna side. Adjust the coupling between the two windings sides to get a maximum signal output amplitude.
The circuit can be powered with a 9 volt battery. It consumes around 20mA only.

Fox Hunt Transmitter Active Components.

T1 = 2SA256
T2 = 3N205
U1, U2, U3, U4 = IC1 = 4093

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the layout of the electricity line around cell phone jammers should be done

And some revise of the layout of the electricity line around  cell phone jammers should be done.
And mobile, China Unicom, not limited to the scope of telecommunications triple-play cell phone number to send, according to the specific needs of custom personalized service. Students as a distinct group, have higher education, higher information needs with the progress, contact television and other media opportunities, the phone reports that the new target audience. Campus mobile newspaper reading population is more focused and precise, and naturally become a new choice in the promotion of business products. Campus phone reported. Campus mobile newspaper "News" is the fundamental content. Planning Students mobile newspaper content loved by readers, of course, we must first understand the interest of the target audience of university students, according to their characteristics, needs.  Industrial environment: As the sponsor reasonable ease the demand for advertising, legal and mobile advertising services, so in fact played a large role in governance spam messages, thereby purifying the industrial environment, the industrial chain win. Status and Prospects of the development of mobile media. As information technology continues to progress, the original mobile phone as an interpersonal exchange of information intermediaries.
Rather to ensure that each piece of information, "Jane and deep." To do Jane and deep "will be a higher demand for editing, you need enough news sensitivity. Such as to make the correct interpretation of the country, the government introduced the policy of involving university students to study or work, and make predictable judgments, and even make incisive reviews, make the appropriate adjustments to help and facilitate college students to use the relevant policies give practical advice. Recommendations for mobile newspaper audience attention of contention. According to the spread scientist Melvin De Fule theory, when major changes occur, the audience will generate an exception to the media rely on. Which media can be timely and adequate to provide information to who he would rely on.  However, todays mobile newspaper is considered to be a subsidiary of the print media, the contents of the value of the performance of the force and the media not been fully recognized and mining. Information personalization. First of all must be aware, mobile newspaper should not just newspapers optional supplement. The mobile newspapers content to get out of the shadow of the newspaper, to form their own style and play their own unique advantages, mining the content of expression, and expansion of channel function.

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Rear Light After Glow For Bicycles

This article is of interest only to readers whose bicycle lights are powered by a dynamo. The laws on bicycle lights in the United Kingdom are stricter than in other countries and a dynamo is, therefore, a rarity in this country. From the point of view of traffic safety it is advisable (in UK obligatory) for cyclists to have the rear lamp of their bicycle to light even when they are at standstill.

In principle, it is not very difficult to modify the existing rear light with afterglow: all this needs is a large enough energy reservoir. Since the after-glow is required for short periods of time only, a battery is not required: a large value capacitor, say, 1 F, is quite sufficient.As the diagram shows, in the present circuit, the normal rear light bulb is replaced by two series-connected bright LEDs, D2 and D3. These are clearly visible with a current of only 6 mA (compared with 50 mA of the bulb).

The current is set with series resistor R1. The LEDs are shunted by the 1 F capacitor, C1. Since the working voltage of this component is only 5.5 V, it is, in spite of its high value, physically small. An effective regulator is needed to limit the dynamo voltage adequately. Normal regulators cannot be used here, since they do not work at low voltages. Moreover, such a device would discharge the capacitor when the cycle is at standstill.

Circuit diagram :

Rear Light After Glow Circuit Diagram

Fortunately, there is a low-drop type that meets the present requirements nicely: the Type LP2950CZ5.0. Of course, the dynamo output voltage needs to be rectified before it can be applied to the regulator. In the present circuit, this is effected by half-wave rectifier D1 and buffer capacitor C2. Diode D1 is a Schottky type to keep any losses low – important for this application, because the ground connection via the bicycle frame usually causes some losses as well. The value of buffer capacitor has been chosen well above requirements to ensure that C1 is charged during the negative half cycles of the dynamo voltage.

Source : www.extremecircuits.net

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Flip Flop Timer Using 4017

This circuit shows how a 4017 CMOS decade counter can be used to build a timer circuit. Push-button S1 will discharge capacitor C1 through resistor R2. When S1 is released, C1 will charge up through R1 causing a rising edge at the clock input of IC1. This causes the output Q1 to go high (to the supply voltage). Current will flow through R4 and LED D2 will light. At the same time C2 will begin charging through preset P1 and R6. When the voltage on C2 reaches approximately half the supply voltage it will reset IC1. Q1 will go low, the LED will go off and C2 will discharge through D1 and R3. The circuit will now remain stable in this reset condition until S1 is pressed again. Preset P1 allows the ON time of the circuit to be adjusted between 5 seconds and 7 minutes.

The current consumption of this circuit in its reset state is only a few micro-amps, rising to approximately 8mA mainly due to the LED current, when S1 is pressed. When power is applied to the circuit IC1, can be in an indeterminate state and the LED may be on. Pressing S1 until the LED goes off clears this condition. Alternatively C2 may be connected to the supply rail (as shown dotted in the diagram) this will ensure that IC1 will always power up in a reset state. A disadvantage of this configuration is that any noise on the supply rail will be coupled through to the reset pin of IC1 and may affect the timing period.

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Rolling Shutter Motor Control

An electrically operated rolling shutter usually has a standard control panel with a three-position switch: up, down and stop. If you would like to automate the opening and closing with a time controlled switch, a few additional wires will have to be connected. Typically, the controls are implemented as indicated in the schematic ‘Normal Situation’. If this is indeed the case, then you can see in ‘New Situation’ how the shutter can be automated with a timer. There is only one method to determine the actual schematic of your control circuit, and that is to open the control box and using an ohmmeter, pencil and paper to check out and draw the circuit. Make sure you turn the power off first though! Connect a 230-V relay (with both the contacts and the coil rated 230 VAC) to the timer.

The changeover switch between automatic and manual control needs to be rated 230 VAC as well and may not be a hazard for the user. The relay and switch are preferably fitted in a plastic mains adapter enclosure with built-in plug, which is plugged into the timer. It is a good idea to check first if this will actually fit. Because of the manual/automatic-switch, the operation is completely fail-safe and misunderstandings are out of the question. The switch prevents the issue of conflicting commands (with disastrous consequences) when, for example, the shutter is being automatically raised and manually lowered at the same time.

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12V Halogen Dimmer

I use a 12V 20W halogen lamp (MR16) and a 4.2Ah SLA battery for my bike light system. The battery has only limited life at this power rating, so I designed this cheap light dimmer to reduce the battery drain and allow for longer rides at night. Based on a simple 555 timer circuit and Mosfet switch Q1, it works by pulse-width modulating the 12V supply to the lamp. The 555 (IC1) is wired as a free-running oscillator, with two different mark/space ratios selectable via a 2-pole, 5-position rotary switch (S1). The third switch position bypasses the electronic circuitry and connects the lamp directly to battery negative. This gives three power levels of about 7W, 13W and 20W. A logic-level IRL530N Mosfet with a drain-source "on" resistance of only 0.1Ω ensures low losses and eliminates the need for a heatsink. An STP30NE06L Mosfet (Jaycar Cat. ZT-2271) would also be suitable.

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Pills Reminder flashing LED

4 - 6 - 8 - 12 - 24 - 48 hours setting, LED or Beep Alert - 9V Battery Supply
A Pills Reminder is a device that operates a flashing LED (and/or a beeper) at a fixed hour interval. A choice of time-intervals as wide as possible is available with this circuit, namely 4, 6, 8, 12, 24 and 48 hours. At first you must choose the hour interval by switching SW1 to the desired value, then apply power by means of SW2. After the hour delay chosen has elapsed the LED will start flashing at 2Hz, i.e. two times per second. This status will last until pushbutton P1 is pressed: then the LED will turn off, but the circuit will continue its counting and the LED will flash again when the same hour interval as before is reached. A noteworthy feature of this circuit, usually not found in similar devices, is that the internal counter is not reset when P1 is pressed: this allows a better time-interval precision.

Let us explain this feature with an example: suppose you have set the time interval to 24 hours and started the Pills Reminder at 8 oclock. Next day, at 8 oclock the LED will start flashing, but you, for some reason, notice the flashes at 8:10 and press P1 to stop the LED. With most devices of this kind, the counter will be reset, causing the LED to start flashing next day at 8:10 oclock. This will not happen with this circuit and the LED will start flashing next day always precisely at 8 oclock even if you pressed P1 at 9 or 10 oclock.

Parts:

R1______________10M 1/4W Resistor
R2,R3,R4_______100K 1/4W Resistors
R5,R7___________10K 1/4W Resistors
R6_______________1K 1/4W Resistor
C1,C2___________22pF 63V Ceramic Capacitors (See Notes)
C3______________22µF 25V Electrolytic Capacitor
C4,C5__________100nF 63V Polyester Capacitors
C6_______________1µF 63V Polyester, Multilayer Ceramic or Electrolytic Capacitor
IC1____________4060 14 stage ripple counter and oscillator CMos IC
IC2____________4040 12 stage ripple counter CMos IC
IC3____________4082 Dual 4 input AND gate CMos IC
IC4____________4075 Triple 3 input OR gate CMos IC
IC5____________4520 Dual binary up-counter CMos IC
IC6____________4001 Quad 2 input NOR Gate CMos IC
D1_____________5 or 10mm red LED
XTAL_________32.768 kHz Sub-miniature Watch crystal
P1_____________SPST Pushbutton
SW1____________2 poles 6 ways Rotary Switch
SW2____________SPST Toggle or Slide Switch
B1_______________9V PP3 Battery Clip for PP3 Battery

Alternative Clock Parts:

R8_______________1K 1/4W Resistor
R9_____________330K 1/4W Resistor
R10_____________20K 1/2W Cermet or Carbon Trimmer
R11______________1K 1/2W Cermet or Carbon Trimmer
C7_______________1µF 63V Polyester Capacitor
IC7____________7555 or TS555CN CMos Timer IC

Circuit Operation:

The clock of the circuit is made of a stable oscillator built around two inverters embedded into IC1 and a Watch crystal oscillating at 32.768kHz. This frequency is divided by 16384 by the internal flip-flop chain of IC1 and a 2Hz very stable clock frequency is available at pin #3 of this IC. IC2 counter and IC3A 4 input AND gate are wired in order to divide by 3600 the 2Hz clock, therefore, a pulse every 30 minutes is available at the clock input of IC5. The division factor of this IC is controlled by IC3B and the position of SW1A and B, selecting from six time-intervals fixed to 4, 6, 8, 12, 24 and 48 hours.

The set-reset flip-flop formed by IC6B and IC6C is set through IC4C each time a low to high transition is present at the pin of IC5 selected by SW1B cursor. IC6A and C4 provide to set the flip-flop also when a high to low transition is present at SW1B cursor. When the flip-flop is set, IC6D is enabled and the 2Hz frequency available at pin #3 of IC1 is applied to pin #13 of IC6D causing the flashing LED operation. The flip-flop can then be reset by means of P1. A master reset is automatically done at switch on by means of C6 and R7.

Alternative Clock:

Sometimes, the Watch crystal can be difficult to locate, or could be considered too expensive. For those willing to avoid the use of a Watch crystal and to accept less time accuracy, an alternative clock generator circuit is provided, directly oscillating at 2Hz, thus avoiding the use of divider ICs. A CMos 7555 Timer IC generates a stable 2Hz square wave, whose frequency must be accurately set by means of two trimmers. R10 must be adjusted first for coarse tuning, then R11 for fine tuning. Setting precisely the 2Hz frequency of this oscillator is a rather difficult task, and can be done with great patience and the aid of a clock, a chronometer or, best, a digital frequency meter capable of measuring very low frequencies. In any case, after an accurate setup, this oscillator showed a very stable performance, not affected by battery voltage variations and an accuracy of about ±30 seconds per 24 hours interval.

Notes:

• Wanting the utmost time precision and if a digital frequency meter is available, a 5-50pF 50V Ceramic Trimmer Capacitor can be used in place of C2. It must be adjusted in order to read exactly 32.768kHz on the meter display with the input probe connected to pin #9 of IC1.
• A Piezo sounder (incorporating a 3KHz oscillator) can be added to provide a visual plus audible alert. It must be wired across pin #11 of IC6D and negative ground, respecting polarities. Remove D1 and R6 if the visual alert is not needed.

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Passive RIAA Preamplifier

There are two types of pre-amplifiers for magnetic phono cartridges. An example of the most common type is the one described in the March 2002 issue of SILICON CHIP. It has the RIAA equalisation network in the feedback loop. The second type was previously used in valve circuits which typically had no feedback loop and used passive RC networks to provide the phono equalization. This experimental preamp was put together using inexpensive FETs to compare the performance of these two types of preamp. The first stage, consisting of Q1 and Q2, is a simple FET audio amplifier, where the FETs are connected in parallel to reduce noise. This is followed by a passive RIAA network consisting of 240kO and 15kO resistors and the associated 0.1OF .022OF and .0047OF capacitors.

Some of the gain loss in the passive network is then made up by FET Q3. It also has a 51kO drain resistor and is buffered by bipolar transistor Q4 which is connected as an emitter-follower stage. All resistors are 1% tolerance metal film type while the capacitors for equalization are MKT polyester types. Ideally, the Idss of all FETs should be matched for both channels. Resistors R3 and R8 should be adjusted so that the drain voltage in each stage is between 13V and 14V, to give symmetrical signal clipping. The power supply can be three 9V batteries connected in series. Current consumption is only 3mA for the stereo circuit.

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USB Printer Share Switch

This simple device allows two computers to share a single USB printer or some other USB device, such as an external flash drive, memory card reader or scanner. A rotary switch selects the PC that you wish to use with the USB device, while two LEDs indicate the selected PC.

The most common way to share a USB printer between two PCs is to use one machine as a print server. However, that’s not always convenient because it means that the server PC must always be on if you want to print something.

Picture of the project:

That can be a real nuisance if you just want to quickly fire up the other machine and print something out. It also means that the two PCs must be networked together, either via a hub/router or directly via an ethernet crossover cable. Another way is to use a dedicated USB print server. However, as before, this must be connected to an ethernet network, along with the PCs. Such devices also need their own power supply, generally cost well over $100 and are overkill if you just want to share a single USB printer between two computers for occasional printing in a home set-up.

Parts layout:

That’s where this simple device comes in. It’s basically a 2-way switch box that lets you manually switch your USB printer from one PC to the other, as required. The switching is performed using a rotary switch, while two LEDs on the front panel indicate which PC has been connected to the printer. This method has several advantages. First, you don’t need to network your two computers. Second, you can print from either machine with the other turned off. And third, the device doesn’t need a power supply.

Circuit diagram:

The circuit uses switch poles S1a-S1c to select either USB socket CON1 or CON2 and connect its pins through to CON3. The fourth pole (S1d) selects either LED1 or LED2, to indicate which PC has been selected.

Source: Silicon Chip14 April 2009

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Low Cost Transistorised Intercom

Several intercom circuits have appeared in www.circuit-lab.com using integrated circuits. The circuit described here uses three easily available transistors only. Even a beginner can easily assemble it on a piece of veroboard. The circuit comprises a 3-stage resistor-capacitor coupled amplifier. When ring button S2 is pressed, the amplifier circuit formed around transistors T1 and T2 gets converted into an asymmetrical astable multivib-rator generating ring signals. These ring signals are amplified by transistor T3 to drive the speaker of earpiece. Current consumption of this intercom is 10 to 15mA only. Thus a 9-volt PP3 battery would have a long life, when used in this circuit. For making a two-way intercom, two identical units, as shown in figure, are required to be used.

Output of one amplifier unit goes to speaker of the other unit, and vice versa. For single-battery operation, join corresponding supply and ground terminals of both the units together. The complete circuit, along with microphone and earpiece etc, can be housed inside the plastic body of a toy cellphone, which is easily available in the market. Suggested cellphone cabinet, with the position of switches, speakers and mike etc is shown.

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CONSTANT BRIGNESS LED AND MUTE CONTROL ELECTRONIC DIAGRAM

CONSTANT BRIGNESS LED AND MUTE CONTROL ELECTRONIC DIAGRAM

The output power of the modules are approximately 220W to 250W into 8? and 350W to 400W into 4?. Complete documentation for the amplifier modules can be found in the documents listed below. AN-1850 LME49830TB Ultra-High Fidelity, High-Power Amplifier Reference Design Although the power supply design is specific to the amplifier modules the concepts and circuit design may be used for any power supply purpose. The power supply is an unregulated design with an option to allow connection to either 120V or 240V mains. The design uses toroidal transformers, a fully integrated bridge, and various rail capacitors for ripple voltage reduction, noise suppression, and to act as high current reservoirs. Additional circuitry to control inrush current on power up and power up/ down Mute control are also included.

The topics discussed inside the application note including the introduction, overview, schematic and design, power supply, additional circuit, inrush current control, mute control, constant brightness LED circuit, summary, and many more.

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2000 Buick Regal Wiring Diagram

2000 buick Regal Wiring Diagram

(click for full size image)

The Part of 2000 buick Regal Wiring Diagram: cruise input, vehicle speed, air solenoid relay, air pump relay, ground destribution, powertrain ctrl module, red wire, black wire, yellow wire

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Rascal Combines Linux and Arduino

Does this sound familiar to you? After spending many hours on optimizing for speed and memory your super-duper MCU application, you can only conclude that it will not run on an Arduino board. You have built the shield (the Arduino compatible extension board) with your special I/O and you wrote most of the software, but these last functions that should add that finishing touch just don’t fit in the board’s memory. Maybe Rascal can help?

Built around a 400 MHz AT91SAM9G20 ARM9 from Atmel, the Rascal is an open source Linux board compatible with Arduino extension cards or shields. Programming the board is easy thanks to a library written in Python from Pytronics that allows easy access to peripherals and shields. The Rascal’s firmware comes with a web server that can serve as a programming interface; you can write your applications directly in a web browser connected to the Rascal board.

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18 LED Dimmable LED Lamp

This circuit is a dimmable white LED lamp array with 18 LEDs. The lamp brightness is regulated as long as the input voltage is above 10.5V. A low-dropout analog voltage regulator is used for a simple and relatively efficient design. The lamp produces enough light to use as a a reading lamp or a small work lamp. 

Project Image

Specifications:

• Power Requirements
• Input Voltage: 10.5-16V DC
• Input Current: 11-150mA at 12VDC

Theory:
The 12V DC input voltage is routed through the 1A fuse and the on/off switch. The 1N4001 diode acts as a crowbar device. If reverse polarity is applied, the fuse will blow and the rest of the circuitry will be protected. Power is sent to the LM2941CT voltage regulator IC. The regulator is wired to produce a voltage range from 5.5V (dim) to 8.3V (bright).

18 LED Dimmable LED Lamp Circuit Diagram

The 4.7K resistor across the 1K brightness adjustment potentiometer produces a non-linear brightness adjustment to compensate for the eyes logarithmic brightness perception response. The LEDs are organized in six series groups of three with a 24 ohm current limiting resistor on each group. This arrangement limits the maximum current through each LED group to around 20mA.

Use:
Connect the DC input terminals to a 12V source, such as a 12V lead acid battery. Be sure to observe the correct polarity. Turn the power switch on and adjust the brightness adjustment for the desired brightness.

Parts:
    1X LM2941CT low-dropout voltage regulator
    1X aluminum heat sink
    1X 1A DC rated fuse
    1X DC switch
    1X 1N4001 diode
    2X 1K 1/4W resistors
    2X 4.7K 1/4W resistors
    6X 24 ohm 1/4W resistors
    1X 1K linear potentiometer
    18X 5mm white LEDs, 20mA max
    1X 22uF 16V electrolytic capacitor
    1X 100nF 25V monoblock capacitor
 

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Roma has developed a small E17 LED Light Bulb

Roma has developed a small LED bulb "LDA4L-G-E17" can support E17 lamp holder, compare with the original LED bulbs such as 12 volt LED lights, new products reduce the size of the power part, the shade of the hemispherical shape is more nearly spherical. LED light source module use the COB construct without mirror, the shape almost identical to  old-fashioned small krypton bulb to achieve 180°light distribution angle.

Prior to the disadvantage of small LED bulb is less luminous part of the light distribution angle narrow, dark horizontal and supply side. The brightness of the new product is equivalent to a 25W mini krypton bulb. The shade is made of the proliferation of Roma self-developed material that can be issued does not point to the warmth of light. The bulb the total luminous flux of 265lm, the power consumption of 4W. The light color than incandescent light color. Design life (the luminous flux dropped to 70% of the initial time) is approximately 40,000 hours. Pricing is open, expect the actual price of less than 2000 yen.

By the way, I konw where to buy the LED lighting such as LED light and best led flashlight at low price,

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Resistor Colour code convertor

This page tells you how to download and use the colour code convertor program
Click to Download
Internet Explorer will respond with a dialog box. You can decide whether to save the program to disc and run it later, or to open it straight away. Either way, there may be a further dialog box, giving dire warnings about downloading software from the internet. (DOCTRONICS knows of no problems with the program, but no guarantee is implied.)
The colour code convertor can be copied and distributed freely, but remains copyright ©. Distribution for profit seems unlikely, but is expressly forbidden.
The program was written using Borland Delphi 2.0.

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How to use the program

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1. Finding the resistor value corresponding to the colour code:
Hold your resistor with the tolerance band (usually gold) at the right hand end:



Within the colour convertor program, click on the FIRST DIGIT drop down arrow to see the choice of colours:

Notice that black is not available as a choice for the first digit colour.
Click on green. The focus moves automatically to the drop down list for the SECOND DIGIT, where you select blue in exactly the same way:

The focus moves again, this time to the MULTIPLIER drop down list where you select brown. As soon as you click the brown, the focus moves to the convert button, and the resistor value, 560 ohm, appears immediately in the result box.
When you select resistor colours in this way, the result appears automatically, without clicking the convert button. However, if you change only the first or second digit colour, without changing the multiplier colour, you will need to click convert to initiate the conversion process.
Note the effect of clicking on the ohm, k and M radio buttons. The colour code for 560 k is given, but 560 Mis outside the normal range of resistor values and generates an error message.

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2. Finding the colour code corresponding to a particular resistor value:
Suppose you want to find the colour code for a 390ohm resistor. The program allows you to do this in two ways. Clicking on the drop down arrow next to the result box gives a list of E12/E24 values from which you can select by scrolling through:

Once you have selected 390 from the list, click on the ohm radio button:

As soon as you click to select ohms, the display changes to show the correct colour code, in this case:

As an alternative, you can enter a number directly in the result box. Numbers with two significant digits are allowed, that is, 1.2, 12, 120, but not 121 or 473. If you want to know the code for 1 200 ohms, enter 1.2 and click k. Incorrect entries, or numbers which do not correspond to E12/E24 values generate appropriate error messages.

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3. Tolerance.
Tolerance refers to the percentage accuracy of the resistor value. Most resistors have a gold coloured tolerance band, indicating an accuracy of ±5%, but other colours are possible and can be selected from the drop down list.

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4. E12/E24 values.
Resistors are manufactured in values which correspond to the E12 and E24 scales. Details are given in the Resistors Chapter. The program indicates whether a particular value is included in both scales, or is an E24 value only.

Back to Resistors

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The Details About How To Purchase The Car Accessories Online

Shopping online has been widely recognized, and become the main way of shopping by many people.
Usually difficult to buy or spend a lot of time to buy things through the Internet can easily set your favorite products, avoid shopping on the road of fatigue, avoid the bargain of the tedious, one-step cash on delivery!
you need to know what the name of the object you want before buying Car Accessories , detailed models, can accurately find the product you need.
I want to teach you is to buy online:
Step one: Open a support page online to buy auto parts.
Registered as a normal user, just fill in login user name and accurate information can be. Click here to say, registration information inside the cell phone number must be correctly completed, the next state to buy accessories can receive SMS delivery, as well as the most important thing is to account if you lose the phone number is your only way to recover password ! Because the site is a registered contractor, so do not worry about the risk of selling customer information.
Step two: Click on the upper right corner shop page "login" button.
In the login page, enter the information just registered "user name" "user password" "verification code" (we are regular users, so do not need to fill out the "User Code"), click on the "ordinary user login" to enter your e- business.
Step Three: Click the top right corner of e-commerce interface "to apply for senior customers."
(Tip: Due to advanced users is the artificial certification upgrade, so the efficiency is low, waiting for the certification period, anxious to buy accessories for friends should be very depressing. Confirmation click on "apply to become a senior account" after we return home, provided us with the Home Online customer contact staff! told him to subscribe to it! play their telephone service can also be urging the opening!) this time we will use a mobile phone, the application is successful, it will be a member of code! Advanced user login is required
Step four: repeat step type "User Code", "username", "User Password" "authentication code", do not forget the user code just made! Click the "Advanced Login" (We are an advanced user, of course, are an advanced user login!)
Self-help e-commerce system into parts inquiries! (If you do not understand the necessary accessories, you can call directly to a salespersons description of accessories to get the parts code, the phone display at the top, or online customer service on the home page to find a solution!).
I want to buy a Corolla front fog lights box. Then in the "cars, manufacturer name, vehicle name, year of manufacture, displacement" field in which the information filled in their own vehicles, because I do not know the parts code directly in the "Part Name" entered above "box before the fog lights" (Even the name is not recognized, then the customer can only ask!)
See the search results, RH and LH appeared in two, to see that, and a left and right, as that is an accessory unit, is certainly a little bug.
The selected accessories to buy, click to the selected parts.
Submit a shopping list on it!

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Multifunction LED lamps

Japan Twinbird recently introduced a very interesting portable LED lamps. The whole body is made from light material, which can create a weak and warm atmosphere and can also be temporary to use as a "lantern" , it is very interesting. This lamp provides two operating modes, including color temperature of 6700K and 2700K color temperature, the machines power consumption is only 0.5W, built-in battery capacity of 700mAh, can last up to 25 hours. But it is not the cheap led light bulbs, converted into U.S. dollars about $155 or so, although it is very interesting, but this price is a bit expensive!

It can also provide background lighting on the bed at night.

Three gear, this is the most bright

This is the medium brightness.

This is the lowest brightness. It is the best choice as a kids night lights.

Normal mode look, the whole body use the optical materials, thus it appears to be white and is not transparent color.


If you want to urinate at night, you can also hold the top of the lamp, the bottom will light into white light, he effect is almost exactly the same as lanterns.

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