Popular Circuits Page 129
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Security system sensors such as motion detectors, reed switches, pressure mats, glass-break detectors, infra-red beams, and conductive film can be very handy for all sorts of things including home automation systems, interactive art installations and....
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A circuit is described that transmits temperature data over an IR link. This allows isolation of the temperature sensor....
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A continuously working wiper in a car may prove to be a nuisance, especially when it is not raining heavily. By using the circuit described here one can vary sweeping rate of the wiper from once a second to once in ten seconds. The circuit comprises two....
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The transmitter runs on only 3V whereas most others run on more voltage. This dirt cheap item uses non-adjustable inductors so it is not possible to tweak for higher output. The common TX2B chip is manufactured by HIGHLAND (SHENZHEN) ELECTRONICS CO LTD and....
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This small device, intended primarily for modellers, allows an instant reading of the time I of a pulse in ms. It can, for example, measure the position of the servomotors, about 1 to about 2 ms, or make repetitive or non-pulsed measurements, such as closing....
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The debate still goes on as to which are better, valves or transistors. We don t intend to get involved in that argument here. But if you can t make your....
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Here is a handy gadget for test- ing of infrared (IR) based re- mote control transmitters used for TVs and VCRs etc. The IR signals from a remote control transmitter are sensed by the IR sensor module in the tester and its output at pin 2 goes low. This in....
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This circuit offers the best of both worlds. It can be combined with a low input offset voltage and drift without degrading the overall system`s dynamic performance. Compared to a standalone FET input operational amplifier, the composite amplifier circuit....
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As shown, the audio ascribe is a microphone, which uses 2 x 2N3904 as the microphone audio preamplifier. The audio/mic ascribe akin is adjustable by agency of a 5k preset / potentiometer. The ambit uses a Colpitts oscillator for abundance generation, which....
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This circuit can be used for large current after use nickel-cadmium batteries, rechargeable batteries, but also as a general low-voltage DC power supply. This circuit by the charging section and the dc output parts. K2 is the fast charge, slow charge selector ..
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This article discusses several opamp-based headphone amplifier circuits, including suggestions for selecting opamps, input coupling and filtering, high current output stages and power supply options. There are no recommendations for specific opamp brands or....
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M½´rklin`s signal braking module, number 72441, solves this problem by introducing a short transition track between ordinary and braking section, and additionally offers a emergency stop section with cut off power in case a loco does not brake in appropriate....
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Direct reading frequency meter by the amplifier, and trigger one-shot circuit and table top components. It can be directly detected in the read head of the table 1mA signal, th..
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A sensitive and reliable rf field strength meter is an invaluable instrument in amateur radio and in radio controlled model area. A field strength meter is used to align an antenna to get the best possible gain, to determine the transmitting range of radio....
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Please operate caution when building this power supply. It is run on standard 117 ac current - and under the right circumstances 117 ac can kill you. Use a plastic enclosure if possible to decrease chances of short-circuiting...
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The pulse repetition rate is selected by positioning SI to the desired position and the rate remains essentially constant when the resistors which determine on-period and off-period are adjusted.
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An old Nokia phone charger with 5. 6 V output, so I tried to adjust it to 12 V. By changing the Zener diode though I manged to do that, but I can`t understand its circuit (I replaced the 9v1 with 16v Zener). I would really appreciate any help to understand....
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Application note explains how to implement a 2.1 (satellite/subwoofer) audio power-amplifier system with 2 x 2W and 1 x 7W of output power from a single 5V power supply....
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The word "demodulator" is becoming standard practice with commercial and military organizations. "Converters" are now often thought of with respect to units automatically changing Morse code to RTTY; changing 8-level to 5-level; changing 50 Baud to 45 Baud,....
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This Project Multi-Pattern Running light is used to generate several designs of Running Lights. We use ten LEDs for display. The designs can be selected by using two switches UP and DOWN. The 8 bit Microcontroller is used to control all the operations. It....
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The unit provides a square-wave output that is rich in harmonic content. The circuit"s output frequency can be varied from 50 Hz to 15 kHz. The heart of the circuit is a 555 astable connected in its equal mark/space mode. The frequency is controlled by....
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Main Power Amplifier OCL 100watt by MJ802, MJ4502. May pleasing of friends at like firm bass and Treble be bold. Because it is Amplifier OCL model Class AB. And it has electric tall power about 100Watt at 8ohm size loudspeakers. Then can use in the work....
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The Ping) is an ultrasonic range finder from Parallax. It detects the distance of the closest object in front of the sensor (from 2 cm up to 3m). It works by sending out a burst of ultrasound and listening for the echo when it bounces off of an object. The....
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4013 dual D-type flip-flop is a monolithic complementary MOS (CMOS) integrated circuit constructed with N- and P- channel enhacement mode transistors. Each....
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The current concept incorporates a wireless transmitter and receiver and is thought to be used for remote controlled airplanes or appliances with two seperate parts. In other words, we have one dedicated transmitter (acquisition, filtering) and one dedicated....
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Here is a 7 segment counter circuit based on IC 74LS90 TTL. This can be used in conjunction with several circuits where a counter to show the progress adds a little more attractive. This circuit accepts any TTL compatible logic signal, and can be extended....
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Using two gates from a CMOS 4011 NAND chip, a simple Squarewave oscillator can br made. Alternatively a CMOS 4001 chip can also be used, or a TTL equivalent. In this circuit the mark space ratio can also be independently controlled by varying the value of....
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Three-terminal regulator device (LM78LXX) has Vout = Vm until the input rises 1.5 to 2 V above the output when the ..
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Ever Imagined controlling your home appliances using your cell phone. You can find a lot of circuits for this application. But they make use of Telephone. I modified the circuit and redesigned it to make it compatible with normal cell phone headphone. Just....
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AM Transmitter. It is illegal to operate a radio transmitter without a license in most countries. This ircuit is deliberately limited in power output but...
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The principle used in this electronic head or tail circuit is simple: a multivibrator controls a flip flop. The multivibrator oscillates as long as the buton S1 is pressed and the flip flop switches on and off with a frequency of several kilohertz. When the....
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This simple AVR Programmer able to transfer hex programs to mostATMEL AVR microcontrollers. It is more reliable than most other simpleAVR programmers available out there and can be built in very shortamount of time. This Programmer support the AVR....
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This LED Flasher circuit is based on the 555 timer IC. The LED Flasher circuit diagram is very simple and require few external components. When the circuit is working the red LEDs will flash at a set frequency one by one like at the railway crossing indicator...
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The circuit switches the current to an electrical heater on and off to maintain the temperature of a room at 25 ±0.5°C. The temperature sensor is a thermistor which provides a differential input (for reduced noise) to an operational amplifier. A 5 kilohm....
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Here is a simple circuit that can be used as a telephone status indicator. When the telephone is in use (off hook) the transistor Q1 switches ON making the red LED D2 glow. When the telephone is not in use (on hook) the Q1 turns OFF and Q2 turns ON. This....
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M1 is a clamp connected to the 24V (dc or ac) power from the gate opener. The diode bridge rectifies the alternate voltage (should the opener use dc current, it merely adjust the positive and negative rail to match circuit polarity), in order to get the....
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555 IC using a delay circuit 2 It is actually a one-shot circuit. A delay time of 1. 1R3 C3. Typically R3 taken lkfl ~ lOMfl, C3-5000pF ~ lOOOpF, gave a delay of 5y s-15min...
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The following circuit shows about 88-108MHz FM Transmitter Circuit Diagram. Features: 1W transmitter Tetsuo style. Component: Capacitor, ....
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Control a car toy. The toy car is controlled via a controller that is connected to it via a wire, so it`s not radio controlled. I would like to use relays to control toy via parallel port. I think there are many relay types and models, and I would like to....
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These short-circuit protected regulators give 6, 7, and 9 V from an automobile battery supply of 13 V nominal; however, they will function just as well if connected to a smoothed dc output from a transformer/rectifier circuit. Two types are shown for both....
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This is a variable power supply controlled with PIC microcontroller. There is LCD display in this circuit which will show the actual value of power supply output. This power supply use push on switch to adjust the output voltage and current value. The top....
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450/800Hz oscillation circuit shown in FIG oscillator is a transformer coupling. The frequency conversion is made different inductance is achieved by changing the oscillation t..
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This one will report about and introduce two very important resources within the one-chip computer -Timing / counter and interrupt system. Say through this, readers can know the operating principle of the timer and interrupt system of the one-chip computer.....
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This simple stereo amplifier uses a National LM3871C. The pin numbers in parentheses are for one channel, and those not in parentheses are for the other channel. The supply voltage can be +9 to +30 Vdc at about 10 mA. The output voltage swing is about....
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The circuit consists of Ql—a phototransistor that responds to an intensity of amplitude-modulated IR light source—and a three-stage, high-gain audio amplifier. Transformer Tl is used to match the output impedance of the receiver to today's popular....
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Even including labor I would think that the real cost of purchasing, stocking, assembly, assembly mistakes, more expensive PCB (more holes, larger), more difficult to tune, etc. would cause it to be much more expensive...
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The analog display consists of a frequency/voltage converter (IC12) and bar-graph segment drivers IC10 and IC11. R34 is the calibration adjustment and is set so that an engine rpm of 5 000 to 7000 rpm lights the first LED (redline value)..
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For maximum efficiency, set MAX_STEPPERS equal to the number of stepper motors that you are controlling (but never more than 4). Motors are referred to by their indices 0, 1, 2 and 3. On the QCard there is a trade-off between the number of motors being....
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In this circuit, a 2-MHz clock is divided by eight in Ul, providing a stable 250-kHz carrier. Ql and Q2 buffer the clock and provide a low-impedance drive for op amp U4, which is a high-gain amplifier and integrator. U4 accepts audio inputs and converts the....
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Is a good touch-down can delay the lamp, the circuit is characterized by: the static power consumption minimal; External switch terminal ..
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The part is deformed because various thermal influence in the course of processing, thus cause the original machining accuracy to be destroyed or caused directly and processed the error. As to precision finishing, the influence of hot deformation is....
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This is an intercom circuit which use LM380 as the audio amplifier and 2 transistors as the microphone pre amplifier. The sound quality will be good enough with low cost building. This circuit consists of two identical intercom units. Each unit contains a....
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A simple remote control tester circuit with diagram and schematic using infra red sensor IC TSOP1738. An LED will blink when IR waves falls on it which indicates remote control functioning....
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The charger is based on the LTC4053a standalone
timer-terminated constant current/constant voltage linear
charger. The LTC4053 features a thermal loop which
maximizes the charging rate under all conditions by
regulating the maximum die temperature. Less....
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As shown, a CD4016 analog instrument is used here as a multiple multiplexed digital output, these output transfer function back to the input. Since the CD4016 is a digitally co..
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The 555 timer chip is a very versatile IC, because when connected correctly, it can it can create pulses of current at specific time intervals decided by the resistor-capacitor (RC) network. When a 555 timer creates pulses in this way, the LED doesn`t stay....
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This project implements a half-duplex, master/slave communications protocol based on RS-485 bus hardware. A Windows PC plays the role of bus-master and several Atmel 8-bit AVRs assume the role of bus-slaves. The Windows part is written in C+, the ninth data....
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This battery tester makes use of an LM3914 bar-graph driver IC. SI selects load on battery under test and programs the volta..
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The circuit in Figure 1 is a simple, low-cost voltage-to-time converter using the ubiquitous 555 timer chip. You can use the IC`s monostable multivibrator as a voltage-to-time converter by connecting the analog-voltage input to the charging resistor, R,....
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Making a timer that is used for circuit training or boxing training etc. Here is the cycle I am looking for. This does not need any input, but to reset the timer to the beginning. its a simple project why not making it simpler by using a microcontroller you....
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I finally gave up on the LM7805 circuitry that comes with these devices. The Harbor Freight 42292 charger used to be controlled by a LM317 variable voltage regulator a long time ago. They probably changed the regulator at some point to lower cost or overcome....
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An RF input is applied to the primary of Tl, which applies equal amplitude, opposite phase RF drive for output FETs Ql and Q2. With no AF modulation at points A and B, the opposite phase RF signals cancel each other and no output appears at the 50 V output....
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The +5V, 1.6A precision switching power supply circuit is as shown in the figure. This circuit increases the photoelectric coupler (CNY75A) and the adjustable precision parallel regulator (TIA31). R3 is the current limiting resistor, R4 and R5 are the....
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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....
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Since modern sound systems usually lack inputs for record players, separate MD preampliers are becoming increasingly popular. They are needed not only by people who still regularly like to listen to vinyl records, but also by those who want tonally....
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This project is not to introduce Tic Tac Toe. Everyone knows this game.
It`s to introduce two features. Bi-coloured LEDs, microcontrollers and the skill of writing an ALGORITHM.
You can use the project to learn the skills of creating the Tic Tac Toe....
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I built the LM386 amplifier section, and it pretty much works. I purchased a five-conductor headphone jack, which passes the left and right channels through to the mono amplifier section when nothing is plugged in, but disconnects the amplifier section when....
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Using circuit depicted in the schematic diagram below, the direction and shaft rotation of stepper motor can be seen on the LED display. Alternative to digital rotation encoder as a digital encoder input, this circuit uses a stepper motor. Here is the....
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I found this circuit really simple and interesting. It is really simple to drive Nokia 3310 graphical LCD by using simple LPT cable and some PC software. Firs of all connect graphical LCD to LPT port according to following circuit: Graphical display needs....
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The operation of the 6CL6 transmitter is actually quite sophisticated, despite the simple appearance of the circuit. The heart of the circuit is the electron-coupled crystal oscillator shown above. This circuit combines the functions of oscillator and....
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Remote tester circuit also resembles the logic of a dark sensor (using BC557) . LDR has been replaced with IR sensor TSOP 1738. The circuit works as a remote tester. Pressing a remote control switch near the IR sensor, switches on the LED D2. I am Sagar....
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Since my page was first posted, I have received a number of emails asking about a high current power supply. I looked around, but couldn`t find one that was suitable. So, I designed this. It is a linear supply, which might have a few of you rolling your....
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Welcome to the weblog where we discuss about electronic circuits schematics, PCB design, diy kits and electronic projects diagrams. A simple DC motor controller circuit with NE555 is shown here. several DC motor speed contro l circuits are revealed here....
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This reference design is a high efficiency, high power factor, digital dimming electronic ballast designed to drive
rapid start fluorescent lamp types. The design contains an active power factor correction circuit for universal
voltage input as well as a....
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This circuit can be built small enough to frt inside a toy. The circuit consists of a relaxation oscillator utilizing one unijunction transistor (2N2646, MU10, TIS43). R2 and C2 determine the frequency of the tone. Pushing the button, SW1 charges up the....
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Using TCM3105 FSK modem chip from Texas Instruments, you can easily build a Bell 202 or CCITT V23 compatible modem. This modem circuit is capable transmitting the data at 75, 150, 600, and 1200 baud, and receive the data at 5, 75, 150, 600, and 1200 baud.....
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Phase noise is a critical performance parameter of frequency synthesizers for wireless applications. RF system designers of phase modulated cellular systems, such as PHS, GSM and IS-54, need low noise local oscillator (L. O. ) or frequency synthesizer....
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Following in the footsteps of the "primitive" but quite successful 4 pin OM802 timer IC manufactured by the original SIGNETICS ITT - GEMINI chip fabrication plants way back in 1969 / 1970, a new and very innovative I. C. known as the " NE-555 " timer I. C.....
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Circuit using the form shown in Figure 1-36, the feedback circuit and the bias circuit separately, Rfl take about 30fl. To ensure put magnification, R queue take lkflo between ..
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Nowadays, it is no longer necessary to use discrete components to build oscillators. Instead, many manufacturers provide ready-made voltage-controlled osci...
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With this sound activated switch, control by sound may be very useful, not just on a robot but also for a bit of home automation, for example a sound-acti....
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Here is an automatic water tank controller that controls the operation of a water pump through a 12V 10amp relay. When ever the water level of the tank short circuits the points A and B in the circuit diagram, the pump get turned off automatically. This home....
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The video master consists of a series of converters that place all your video sources on unused UHF channels, which then combines them with normal TV channels (terrestrial or cable into one cable). That one cable can then feed several TV sets for....
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This is Circuit Diagram 0.1 Alpha Software, all free to download and also available open source....
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Cheap PIC controlled Helmet Camera using Sony LANC (Good for Extreme Sports) This Instructable will show you how to make a cheap Helmet Camera which can be....
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Normally analogue-to-digital converter (ADC) needs interfacing through a microprocessor to convert analogue data into digital format. This requires hardware and necessary software, resulting in increased complexity and hence the total cost. The circuit of....