Top Circuits Page 49
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Many modern audio recorders is now compatible with digital input S / PDIF (Sony / Philips Digital Interface). Devices like CD Changers, MiniDisc recorders, computer sound cards and the like. working with digital signal just with protocol S / PDIF. Digital....
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This circuit was designed to control a 32 channel Christmas light
show from the PC serial port. Originally designed with TTL logic,
it has been simplified using CMOS circuits to reduce component
count. It is a fairly simple, reliable circuit that....
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ADC0809 is an 8-channel analog switch with an 8-bit successive approximation A/D converter. ADC0809 8-channel analog switches can be realized now 8 to 1, an address latch and d..
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Another example given in AD574 and PC bus. The figure for the AD574 converter Ul, U2 is 74LS245 bidirectional data buffer, U3 of 74 Lsoo two-input AND gate, U4 to 74LS125 tri-s..
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Circuit is shown. It consists of a temperature sensor, temperature control of electronic switches and circuits composed vocal language. In the hot summer season, PCs central pr..
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You must be able to recognise components such as capacitors, diodes, zeners, transistors and resistors to build 5x7 Display project. This information is covered in our BASIC ELECTRONICS course and a complete set of circuit symbols can be found HERE...
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This is one of the most accurate and simplest LC inductance / capacitance Meters that one can find, yet one that you can easily build yourself. This LC Meter allows to measure incredibly small inductances starting from 10nH to 1000nH, 1uH to 1000uH, 1mH to....
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A useful operation for the cars is delayed extinguishing internal lighting cabin of passengers, after close some door of car. Certain cars allocate this operation from their constructor. Oldest sure do not allocate such operation. This delay makes this....
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When we step on the car' s brake, then together with the classic rear STOP ,the third STOP which is situated in the middle of the back half of the car also switches ON. This is the classic function , is to be found in all modern cars. The difference with the....
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When the brake pedal is on depressed, battery positive voltage normally applies through the STOP fuse and stop light switch to terminal STP of the ECU, and the ECU turns the cruise control off. A failsafe function is provided so that cancel functions....
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What's so special about this circuit? Well, the first third-brake light I installed I had to pull a wire from the
Third Brake Light all the way underneath the carpet to the brake-pedal-switch and I thought it would be easier to
pluck the signal of both....
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This is basically a flasher circuit modified to turn on and off a bulb instead of a LED. It uses a 555 timer IC working as an astable multivibrator. The flashing rate can be varied from very fast to a maximum of once in 1.5 sec by varying the preset VR1...
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This unique circuit makes your dome light look cool. Usually when the car door is closed, the dome light just goes OFF. With this circuit, you can have our dome light fade slowly in brightness and finally go OFF. This slow dimming of the light gives a very....
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1 Bute CD12V Lee output end of the eight-connected MOSFET power transistor BU * {1RF744) im JUV bone made this power MOSFET is turned on and should go off repeatedly called to ask L packet..
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A simple but useful circuit for all they have problem with parking car, in spaces without good visibility. The electric circuit appears in picture 1. It is constituted by the IC1 and components round he. When the car bumper touch soft and push lightly the....
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Tihs circuit has: automatic switch on on rear gear. led-bargraph display. audible bleep on last led. "good old" design style, no microcontrollers! Based on an ultrasonic amplifier from an article seen on a 1982 magazine, it was once installed on the rear....
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Circuit works: lC is a 555 IC. Incoming calls, 220 V electricity through R1 Buck, VD1 rectifier, DW regulator, C2 filtered to give 12 V DC voltage of about...
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One-farad capacitors require some care. It`s a common knowledge that they must be pre-charged with a current-limiting resistor before plugging in. It is less common knowledge that those fifty-dollar `smart cap controllers` are in fact very simple devices,....
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If the amp is built on bipolar transistors, and the preamp/crossover on FETs, then they were designed by different guys, right? Not this amp. Here, a strong, experienced designer`s hand is evident from schematic to parts layout, PCB routing and general....
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Anti-theft car audio system circuit is shown, which is taken from the car battery 12V DC power supply. When after closing the switch S1. Optocoupler IC1 light emitting diode is..
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This is an early picture of my discolight effect. Because of the AGC circuit theres no need for potentionmeters for sensitivity adjust. I replaced them with trimmers. Now the microphone is on the control electronics because theres no need to place it outside....
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No description available...
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From 230 V AC a DC supply of + 5 V is obtained. The power supply is given to the other blocks. The pulse generator at a particular frequency generates the clock pulses. The clock pulses are counted by a counter and gives output after every 10 pulses. The....
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Integrated-circuit U1-an LF351 or 741 op amp-is used as a comparator to control the light. Resistors R2 and R3 provide a reference voltage of about 2.5 volts at pin 3 of U1. When daylight falls on light-dependent resistor LDR1, its resistance is low: about....
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This circuit works REALLY well. Notice how it will fire even in complete silence. This provides a sort of automatic gain control...
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There is, and always has been, a marked lack of good, inexpensive lighting controllers for small theatre groups or musicians. The LX-800 Lighting System was designed with these applications in mind...
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The strobe controller is essentially a stand-alone device, even though it is part of the console PCB. It connects through a two-wire cable to the remote strobe head. Control, input source selection and output routing are on the console. The input to the....
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Since the circuit operates at greater than mains potential and is not isolated by a transformer, it is extremely dangerous. The DC operating potential is about 340V, and there is more than enough stored charge to kill you many times over (although in my....
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Anyone who has been to a night club, concert or school dance has probobly seen a colour organ. Colour organs cause lights to blink and flash to music from your TV, stereo, guitar and even your own voice. The colour organ presented here needs no connection to....
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Sensing unit consists of infrared emitter OP295 to produce the infrared beam, & two detectors in front of the emitter to detect the infrared beam OP598. Since the main idea in this device is to know person direction; and so, to get this approach, we have to....
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200W Lamp Flasher is used to flash lamps, bulbs and halogen lamp to give your product that attracting look...
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Light Sensitive Switch is a simple project which operates a relay when the light falling on the LDR goes below a set point. ..
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This is a very basic power failure lighting circuit based around a relay. This simple circuit has many uses, from lighting up rooms and walkways in the case of a power failure, to monitoring and security uses. There are many different power failure circuits....
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The Sun - Up Alarm can be used to provide a audible alarm for when the sun comes up or it can be used in a dark area and detect when a light comes on. It can also be used to detect a light beam, headlights etc. The circuit works as follows. The....
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The circuit connects to the speaker outputs of your stereo or to the back of your speaker. The music passes through the transformer and the volume level is adjusted by the 5k ohm pot. Each light bulb is turn on by a different frequency of sound based on the....
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This kit is the most basic, practical circuit to build using an
LDR to turn on a relay. The two transistors connected as a
Darlington pair give the circuit enough sensitivity, while
the trimpot give sensitivity adjustment. The switching
point of the....
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With RFT illuminated, point R goes to 0 volt and LM runs. With LFT illuminated, point R goes to 0 volt and RM runs. With RFT and/or LFT not illuminated, points R/L go to +9 volt; P1 and P2 controls threshold point when RM/LM stop or start running. Remember....
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Capacitor Cl is connected continuously through the supply of 3 volts to 10 megohm resistor Rl. The capacitor is charged (relatively slowly) to 3 volts. The wink SWI is closed, it connects the charged capacitor (Cl) in series with C2 and R2. The capacitor C2....
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Using only a NE: automatic light sensor circuit composed of 55 groups, so that people can rice lights, people take the lights off. } N supply route VD1, vS, C. , (1 and R. composition, power and (1, both ends of the Sichuan Hl 12V input DC ..
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NE555 time base circuit with AC solid state relay SSR may constitute automatic light switch circuit, the circuit shown in FIG. From the figure can be seen during the day due to incandescent EL photosensitive resistor circuit automatically fall off when the..
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The author's articles of months past focus on the application of 32-bit high-powered processors to amateur robotics and more recently applying CPLD technologies to the same. Continuing on this high-tech trend, this article will cover the concepts and....
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This Alarm can be used to protect your property, Inside or Outside.
And it can protect a Very Large area such as the complete perimeter of your yard.
Be Aware: There are some Possible Drawbacks: Snow or Fog could Block the Beam,
Giving a False Alarm...
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The following diagram shows the basic laser pointer circuit. It is identical to the infrared circuit except that the infrared LED`s have been replaced by the laser pointer unit.
Due to the long range of these devices this detector method can easily....
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The temperature controller must meet some unusual
requirements. Most notably, because of ambient temperature
variation and laser operation uncertainties, the controller
must be capable of either sourcing or removing heat
to maintain control...
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DC power supply is a helium-neon laser excitation power supply currently used the most common form of power, there is shown a laser printer used in the road, Tl as power transf..
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Thanks to the S6986, the circuit is very simple and requires few components. D2, D3, D5 and D6 forms a bridge rectifier allowing to plug the sensor connector brick in any direction. C1 filters power supply, it must be connected near to IC1 to bypass it....
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The first 5 circuits described in the following sections were reverse
engineered from commercial HeNe power supplies. There may be errors in
transcription as well as interpretation. In many cases, the transformer
secondary voltage was not marked and....
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Laser based projects used to be expensive, until the development of solid state lasers. This project is designed for the entry level laser experimenter. The circuit allows any two computers with serial (RS-232) communication capability to communicate over....
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This document tells about one of my experiments with semiconductor laser modules. I bought one semiconductor laser for all kinds of experiments. This TIM202 module is a small (38x14x14 mm) semiconductor laser module, similar to those types used in laser....
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FIG 220V AC by the step-down transformer T, VD3 ~ VD6 bridge rectifier and a three-terminal voltage regulator blocks A2, stable 12V DC voltage output for digital integrated cir..
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In the laser tube drive circuit are often provided with a photodiode, which generates a laser beam is proportional to the intensity (optical power) of the current, but in response to this type of photocell mostly relatively slow, generally can not track....
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Circuit T as principle: In this circuit, a laser diode LED, as a light hair emitter, in addition to other properties may also be used similar light emitter laser diode substitu..
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4000 Series 4011B is (NAND gate) by the 4AI NAND gate circuit group to form two loops unstable multivibrator. L NAND gate and NAND gate 2 is ikHz (determined in accordance with..
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This project I made for my little daughter. It is 24 channel light illumination. The schematic is very simple ? 24 LED?s, 1 MCU and some additional components. The main principle is dynamic indication, which is usually implemented for control of 7-segment....
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An ultralow dropout current source maintains accurate LED current at very low ILED voltages. Automatic mode switching optimizes efficiency by monitoring the voltage across the LED current source and switching modes only when ILED dropout is detected. The....
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The LTC3201 contains overtemperature protection and can survive an indefinite output short to GND. Low external parts count (one small flying capacitor and three small bypass capacitors) and small MSOP-10 package size make the LTC3201 ideally suited for....
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This project uses a 3909 IC and a few other parts; power is 1.5 volts DC...
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The LT®3465/LT3465A are step-up DC/DC converters designed to drive up to six LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents and eliminates the need for ballast resistors. These devices integrate the Schottky....
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The circuit shown in Figure 1 is specifically designed to
control a single 1W CCFL. T1, Q1, Q2 and associated
components form a current fed resonant Royer converter
that produces a high voltage at transformer T1s secondary
winding. The CCFL current is....
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A tiny sandwich flag connected perpendicular to the motor spindle aids observation of how long it takes to complete one full rotation. This worked initially, as each burst from the capacitor barely moved the flag 1/4 of a rotation. As the circuit variations....
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Figure 2 shows another approach that requires additional components but delivers the full magnitude of the voltage ramp to Pin 3 of IC1 and provides the approximately 1V-dc offset that Reference 1 requires. Transistors Q1 and Q2, resistors R1 and R2, and LED....
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Figure 1 presents an alternative to the typical boost power regulator. A buck-converter IC, IC1, generates the higher voltage that the white-light LED needs. An internal buck power stage connects between VIN and PGND, sourcing current to output Pin L. This....
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The circuit in Fig. 1 uses a single bicolor LED to
indicate both power-on and blown-fuse conditions.
Regardless of the condition of the fuse, the green
side of the LED is always on for each positive
half-cycle of the ac input. With a 120Vrms ac
input....
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The LED flasher circuits below operate on a single 1.5 volt battery. The circuit on the upper right uses the popular LM3909 LED flasher IC and requires only a timing capacitor and LED. The top left circuit, designed by Andre De-Guerin illustrates using a....
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To model an LED in PSpice, use the diode model. You can set the IFK and ISR parameters in the diode model to zero; Figure 1 shows the resultant PSpice diode forward-current model and corresponding equations. As the equations in the figure show, you can....
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White LEDs are popular for portable equipment LCD backlights because they are less complex, less expensive, and smaller than CCFL backlights. Portable equipment like PDAs, cellphones, and digital cameras require backlights because they are converting to....
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Next is the microcontroller or MCU. In previous projects, we used the Atmel AT89C2051. However, the I/O port structure is not quite suitable for this application so we have used the similar Atmel AT90S2313. The main feature influencing this decision is that....
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Figure 1 shows the classic way to use a backlight-driver IC to provide dimming. By modulating an external PWM signal, the circuit controls the white-LED current. By adjusting the on/off-time ratio, or duty cycle, the circuit can provide drive ranging....
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The circuit mixes LEDs of different forward-bias requirements, yet keeps the loads reasonably well-balanced through use of a current mirror comprising transistors Q1 through Q4. It also eliminates the need for a separate current-limiting "ballast" resistor....
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The circuit in Figure 1 represents one method to switch a bipolar, two-color LED using an SPDT mechanical switch or relay. This circuit wastes power and does not work properly if the power-supply voltage is not substantially more than the sum of the LEDs`....
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The compact circuit (Figure 1) overcomes these problems. The regulated buck/boost charge pump in a small µMAX package (U1) has a 100mA output-current capability. Configured as shown, the circuit directly regulates bias current flowing through the white LED.....
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The rotary switch is available for $5.00USD as of 2003 from DigiKey under part number EG1951-ND or EG1952-ND. It is a real pain to operate this circuit without a proper switch. You can put multiple 4017 ring counters in series to reduce the duty cycle in....
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Figure 1 shows the LT1618 driving a 1W, white Lumileds (www.lumileds.com) LXHL-BW02 Luxeon LED.
You need no external op amps for this compact approach. The LXHL-BW02 has a forward voltage of 3.1 to 3.5V for 250 mA of current. Although the maximum dc....
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The LT®1932 is a fixed frequency step-up DC/DC converter designed to operate as a constant-current source. Because it directly regulates output current, the LT1932 is ideal for driving light emitting diodes (LEDs) whose light intensity is proportional to the....
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Figure 1 shows the various LED-circuit configurations, and Figure 2 shows the timing to generate all three colors from bicolor and tricolor LEDs, although using only one LED`s operating current. Note that the driver for the bicolor LED must be able to sink....
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The basic circuit illuminates up to ten LEDs in sequence, following the rhythm of music or speech picked-up by a small microphone. The expanded version can drive up to ten strips, formed by up to five LEDs each, at 9V supply. IC1A amplifies about 100 times....
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Powered from two alkaline cells, the circuit in Figure 2 can
illuminate a 1W LXHL-BW02 LumiledsTM white LED with a
constant 320mA current at 85% efficiency. The forward
voltage of the 1W LED, 3.6V typical, requires a boosted
voltage from the 2-cell....
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The circuit in Figure 1 allows you to compensate for both of these temperature-dependent problems, using only the TSF-102 sensor from Texas Instruments (www.ti.com). The device is a temperature-dependent positive-temperature-coefficient resistor with a....
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This application note describes how LEDs (including white LEDs) work. The note also explains how to drive them in battery-powered LED applications, including lithium-ion (Li+ or Li-ion), nickel-cadmium (NiCd), and nickel metal-hydride (NiMH) rechargeable....
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LT3466 is a dual full function step-up DC/DC converter specifically designed to drive up to 20 White LEDs (10 in series per converter) with a constant current. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and....
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The circuit in Figure 1 is similar in principle to that of a previous Design Idea (Reference 1) but offers improved, more reproducible performance. The output current is almost constant over an input-voltage range of 1.2 to 1.5V and is insensitive to....
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The LED driver in Figure 1 illuminates retinal neurons in a biological experiment that has similar requirements. For a given LED at a given current, the intensity is stable, so switching a stable current is a simple and effective way to obtain the needed....
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Figure 1 shows the relative responsivity and emission spectra for an Infineon (www.infineon.com) SFH409 LED. This infrared GaAs LED has peak emission at 940 nm with a half-peak bandwidth of 50 nm. In detection mode, it peaks at 920 nm with a half-peak....
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Using just four transistors and six resistors, this circuit provides switchable, constant-current drive for an LED and indicates both open- and short-circuit fault conditions (Figure 1). And there`s a bonus, too. Control signal VCONT switches the LED on and....
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Below is a proof of concept circuit which needs improvement. The part values shown will run a high efficiency red LED with a Vf of 1.9V from only 2 nicads, right down to 2 volts. For a white LED you will need more batteries and you must increase the 1.0K....
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I don`t know why, but people like blinking lights. You see LED chasers everywhere, in TV shows (Knight Rider), movies, and store windows. This schematic is my version of a simple 10 LED chaser. There is no 555 timer used because at my local electronics store....
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The circuit in Figure 1 provides 32 steps of brightness controlfrom 0 to 100%for a backlight or instrument panel, using just two general-purpose-microprocessor signals. In addition, the circuit requires little board space, because it uses only three SOT-23s....
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The TL082 (Or a TL072 also is OK) Creates an Adjustable Sawtooth Generator. (It also has a Square wave Output, but it isn`t used here.)
The Left and Right LED`s are Connected in Series and if this circuit is used on a 12 volt system, and if a person....
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This project is also an essential part of the expandable analyser to be published soon (or perhaps "eventually"), and one meter circuit is used for each frequency band. There are many other uses for a simple LED VU meter. They are ideal as power meters on....
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This circuit operates two LED strips in pulsing mode, i.e. one LED strip goes from off state, lights up gradually, then dims gradually, etc. while the other LED strip does the contrary.
Each strip can be made up from 2 to 5 LEDs at 9V supply. The two....
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This design reconfigures the APD-bias IC, IC1, to allow its low-voltage DAC output to modulate the high-voltage, current-sense feedback via a high-voltage-output transconductance stage comprising Q2 and Q3. These two complementary transistors provide....
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Efficiency can be increased by using a germanium transistor at the 33 ohm current sense resistor, and by using a proper torroid core in place of the crappy ferrite bead. Single AA cell powers two LEDs at constant current....
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For those who dont like microcontroller projects, pretend the micro is a dedicated LED driver IC that just happens to have been designed to control 30 LEDs in the shape of a Heart (what a stroke of luck!). And it wont be declared obsolete just after....
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Here is the schematic, PC board pattern, and parts placement for a "Fantastic Atom Expander". This circuit produces an "exploding atom" effect using 98 LEDs. # The LEDs can be any colour but blue. For a very interesting effect, make one ring red, the next....
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The LT®3465 white LED driver is ideal for backlight
circuits in small, battery-powered portable devices
such as cellular phones, PDAs and digital cameras. The
LT3465 includes important features such as automatic
soft-start to prevent large inrush....
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White LEDs are widely used in small LCD backlight
applications for simplicity, high reliability and low cost.
However, due to variations in the forward voltage drop of
white LEDs, matching the brightness becomes a major
design consideration for multiple....
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The circuit forces a current to build up in the L1 coil and the LEDs until the voltage developed across R3 reaches VFB/3.3V. At this point, power switch Q1 turns off, and the magnetizing current keeps circulating in the coil and LEDs, thanks to....
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The circuit in Figure 1 comprises IC1, a Microchip PIC12F675 microcontroller driving IC2, a Kingbright AAF5060PBESEEVG "rainbow" indicator that contains three ultrabright LED chips (red, green, and blue) within one package. Modulating each LED`s duty cycle....
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This is a pocket-sized LED flashlight operating with only one AAA battery. However, the super high luminosity LEDs(blue,green or white) require at least 3.5 volts of forward voltage. This flashlight is boosting input voltage up to operating voltage of a LED....
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The circuit in Figure 1 uses IC1, the integrated offline Viper22A switching regulator in a constant-current configuration to drive two to eight 1W LEDs. The circuit operates by monitoring the voltage drop across the sense resistor, R6, and uses this voltage....