Top Circuits Page 241
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The elements diameter of the antenna may vary between 5. 8mm and the dipole diameter may vary between 8. 12mm (12mm recommended) without the need of changing anything to the length or spacing. All elements except the dipole are electrically connected to the....
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The regen is basically an oscillator circuit with a gain control that allows the user to adjust the feedback to a point just below oscillation or, quite often, just above the critical level such that a small oscillation is present. The typical regen uses a....
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Input signals from the power line are coupled through C23 and R19 to the input filter network. C23 must be rated at 600 volts. Switch 52 is used as an attenuator. Components C2 through C7, L1 through L3, R1, and R20 form a triple-tuned bandpass filter having....
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Generate the 10-Hz waveform that modulates the 3-kHz tone that is generated by U1C and D, Ql drives the transducer through a 8-Q:l-kS2 transformer. R4 might require slight changes (G‚ ±1 KOhm) to optimize sound intensity. Warning: Could cause hearing loss if....
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Integrated circuit Ul (an NE602 double-balanced mixer) is a combination oscillator and frequency mixer. Signals from the antenna input (at Jl) are fed through dc-blocking capacitor C1 to the RF-gain control, Rl, and fed to the input of Ul at pins 1 and 2.....
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This tutorial explores a common digital concept using the NI Multisim software environment. It examines a four-bit counter that uses a 555 timer IC to generate the clock signal. This tutorial takes less than 30 minutes to complete and consists of 37 steps to....
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Using a triangle wave and a comparator, a pulse-width modulated signal can be created. We will use the DAC as our input signal and the resulting output signal will have a duty cycle that is proportional to the input voltage. We will then use the PWM signal....
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With the comparator output driving an LED, the next step will be to sense the intensity of the LED. This lab will build a light detector circuit using an op amp and an everyday light emitting diode (LED). It`s common knowledge that when a current flows....
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This lab will demonstrate the theory and operation of non-inverting amplifiers as well as their practical application to amplify the signal of a microphone. We will construct a non-inverting amplifier to increase the output signal of a microphone, and use....
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As part of the National Instruments Tinker, Learn, and Do Engineering with NI myDAQ course ware, the hands on experiments demonstrate the wide range of possibilities of using NI myDAQ hardware. The 10 lab experiments cover a wide range of topics including....
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The NI 655X is a versatile high-speed digital product that can interface to many different technologies. This application note shows how to interface the NI 655X to LVDS devices. Low Voltage Differential Signaling (LVDS) is an emerging differential digital....
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NI Multisim software offers advanced virtual instruments and analyses to help you gain a deeper and more complex understanding of the operation of your design. One of these tools, the measurement probe, can be a quick and functional interface to the....
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National Instruments Multisim now has microcontroller unit co-simulation capabilities, allowing you to include a microcontroller, programmed in assembly or C code, within your SPICE modeled circuit. The MCU functionality in Multisim enables students,....
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The overall block diagram of the system. Audio comes in at the left, and is summed, differenced, multiplied, delayed, filtered, and all other imaginable manipulations. The output is a set of 5 discrete audio channels plus one low frequency effects channel.....
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The white feedthroughs are for the attachment of the RF high voltage to the D`s (not shown). The copper pipe normal to the pipe is the vacuum line. The D`s have screw posts on the side for attachment to the RF power supply leads (curled copper wire). You can....
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THE L3 WIRE - AMPLIFIER TYPE NH19-6112 P. REWIERSMA NIKHEF-H AMSTERDAM FEBRUARY 1986 Abstract: This note describes in detail the design considerations and performance of the hybrid linear amplifier for the muon detector in the LEP L3 experiment. The L3 WIRE....
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The motor controller is a custom built box that is a combination of custom printed circuit boards, the Pico Systems Universal Stepper Controller card, gecko G320 motor drives and internal power supply. The motor controller also links to the servos which....
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Development of the whole system required an exhaustive identification of all processes of the laser controller. I started with this diagram which outlines the major physical components that will be used for the cnc laser. The laser has a power supply, a....
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The nixie tube clock consists of a high voltage power supply, seven rings counters and an Atmel AVR processor. The power supply is shown in schematic Schematic 1. It takes 12 volts AC and converts it to DC which drives the Maxim 1771 switching power supply....
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LCD segment number growth increases the pin number of package in LCD driver. The LCD driver IC with key-scan function makes the burden of microprocessor light. But it increases the pin number more, and it is difficult to be mounted in the board for large IC.....
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When deciding how to move the robot through the house, the designers realized that precision movement would be necessary in order to avoid touching the walls and receiving penalties. In order to achieve the required precision in movement, it was decided that....
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AD9835 is a DDS (direct digital synthesis) chip from Analog Devices. It contains a phase accumulator, sinewave table, and 10-bit D/A converter. In can be used for phase and frequency modulation by selecting the phase and frequency of the signal either under....
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You should have the GNU tools configured, built, and installed on your system. In this chapter, we present a simple example of using the GNU tools in an AVR project. After reading this chapter, you should have a better feel as to how the tools are used and....
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I found that my sprite, burdened with an extra electrical load from an electric cooling fan, just barely kept the battery charged. My intended solution to this problem is an electronic voltage regulator; however, it seems obvious that, before changing the....
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The 900 Hz tone is generated with an LC-oscillator. The "L" part of the "LC" is provided by the inductance of the oscillator`s output coupling transformer T1. It is a variation on one of the two standard Hartley oscillator configurations (named after its....
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The circuitry for the tone detector, solenoid driver, and motor speed control (paper transport and spindle) is rather straightforward. A solid-state implementation of the driver circuit typically needs a diode (installed with reversed polarity) across the....
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Clip sync output to TTL level seems to take some more time to fit the extra parts on the board; as a quick fix, put a ZPD4. 7 (4. 7 V Z-Diode) between SGand ground at the POWERswitch (ring to SG) and a 1k resistor between the SGoutput from the BOTPCBand the....
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One of the principal choices in phono preamplifier design is between active (feedback) and passive equalization. The ideal feedforward preamplifier for a moving magnet cartridge would have about 40dB gain prior to the equalizer (more for low-output moving....
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The power supply has been simplified- Power transformers and rectifiers have been omitted and some parts have been omitted from the MOSFET voltage regulator circuits: 1N5242 zener diodes between the source and gate and 10k resistors in series with the gate.....
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As my principal hobby interest is now photography and I work crazy long hours at Imatest, I won`t have much time to update this article or answer difficult questions. James E. Lanier`s PSPICE Triode Calculator is a promising program for finding tube model....
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It uses body heat to locate and track its human master. At heart of this heat seeking capability is the Devantech TPA81 Thermal Sensor Array. The TPA81 consists of an array of eight detectors mounted horizontally. Each of the detectors is capable of....
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The term Arduino actually refers to a system of components that include the board, the microcontroller, the boot-loader, and the programming environment. It is a system designed to `protect` the user from a lot of the complication that is part of....
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This page serves as documentation for the circuits that I have built which make use of the Modular Signal System first documented by Gregg Fuhriman in Railmodel Journal, and further documented on the Free-mo. org website. This effort was an experiment on my....
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The remaining equipment is installed at the train layout`s computer interface. The interface I used here is a Lenz LI100F configured to communicate at 9600bps. Both the LI100F and the XBee Explorer serial are configured as DCE (Data Communications Equipment)....
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At the beginning of a design process the designer has to verify which circuit structure is suitable for a given purpose. At this stage numerical and symbolic analysis are of little use. There are no numerical values for conventional simulation with programs....
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Tomas OK4BX came prepared with an excellent slideshow presentation of the DDS-driven MEPT that he and his father recently put on the air. W0EA was able to show us the schematic and PCB layout of the amplifier T/R switch that he just sent out for....
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The Nutchip decodes the signal, differentiating between immediate and delayed sensors (aside from true remote control signals used for switching the circuit on and off). As for all radio-based designs, always remember that a good radio receiver cannot....
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This project introduces a fundamental electronics building block: the counter. Building yourself a simple circuit which increments display count every second, you are going to learn how displays work and how to drive them in the right way. For those who....
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The schematic diagram is quite straight forward. SW1 is a pushbutton used for starting the timer. The oputputs are set logic level 0 when the timer is not triggered, and to logic level 1 when the timer triggers. The relay driver transistor TR1, which....
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Although the Audionics CC-2 is named after Cliff Moulton (Audionics` chief engineer) and Charles Wood (Prez of Audionics), as usual in the business world, the principals in the company masked the identity of the real creator - Bob Sickler, whose name appears....
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Mixers (sometimes known as frequency converters), modulators, balanced modulators and other circuit blocks are considered below. Each works on the same basic principles. A mixer circuit normally has two inputs - from two separate signal sources. In the....
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Those variations, (in effect an alternating signal), will be passed via the coupling capacitor to the next stage - shown by the arrow to the right. We can replace one variable resistor with another. Consider R1 to now be replaced with any one of the devices....
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V-USB is a software-only implementation of a low-speed USB device for Atmel`s AVR ® microcontrollers, making it possible to build USB hardware with almost any AVR ® microcontroller, not requiring any additional chip. Supports multiple endpoints: one control....
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A listener standing some distance from a sound source will perceive sound that is actually a combination of direct sound and indirect sound that has been reflected from the boundaries of the listening area. The reflections are referred to as reverberation.....
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For the wiring of the display we first of all take the ribbon cable and solder it according to the following circuit diagram on the 25 pin sub-d (parallel port) plug, whereby in my small circuit diagram I described the rear side - consequently the solder....
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This Atmel IC, is clocked in the circuit with a 12 MHz quartz and provides a communication between the Infrared receiver and the PC, so that this signal can being processed by infrared receiver programs like Girder. As soon as a valid RC5 signal of the....
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The wiring schematic played a big roll on the robot. This diagram is used to graphically display all the wiring of the motor controlling micro-components that gave the robot the ability to physically move forward, backward, left, right, and stop. (This....
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The design of this project depends on the sensors. The control module and the robot both contain sensors. The computer, in turn, analyzes the signals to make the appropriate output actions. As previously mentioned, the potentiometers are the sensors on the....
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The momentary switch used was rated for 10A for safty. If the switch was rated for too small a current, the instantaneous current for the first millisecond would fuse the switch contacts together. To achieve objective 3, some sort of switch that can vary....
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This circuit is a missing pulse detector. It is used in the_ General Purpose Controller Board with Basic Stamp 1. This circuit is used to monitor an input pulse train, and when a pulse is missed the 555 timer output will switch low. For the General Purpose....
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A discussion of the Williamson Amplifier should be first preceded by an overview of its context in the evolution of the vacuum tube and its application to high fidelity audio reproduction. Transformer coupling was widely used pre-war because it was simple....
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All feature crystal-controlled transmitters and tunable superregenerative receivers with RF preamplifiers designed for operation on the 2, 6 or 10 meter amateur bands. The highly sensitive receivers pull in signals as low as 1 microvolt and produce complete....
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After repairing a couple of Hewlett Packard vacuum tube voltmeters, I read up on some of the company history. I was able to locate a HP-200C oscillator. This HP-200C is very close in design to the company`s initial product. It is a Wien bridge....
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This National Radio Institute radio kit covers the AM broadcast band from 550 to 1700 KHz. The set was designed to be constructed as part of a radio course taught through NRI. In contrast with some other correspondence course kits such as a later NRI....
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I designed the PC Power-on Combination Lock (PCPCL) last year for my GCSE Systems & Control project. The exam board stated that we must design a product under the broad category of `Safety and Security`. I already had in mind some ideas for what I wanted to....
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The next job is the LNA transistor replacement, but the trouble is repeated already within next contest. Such problem is usually result of unsuitable time sequence of switching between receive and transmitting, where due to different delays (for example by....
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Part of this circuit is turning the analog signal coming from the reversed LED (sensing mode) and amplified by the op amp into a digital (on/off) signal. I got rid of all that. This is the modified simplified version of the schematics: Another possibility is....
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If the audio output is connected to equipment that has a balanced input circuit with a separate ground connection, the ground connects to OUTPUT terminal # 1. The PZ-2LA can also be powered by an external AC or DC source between 8 and 24 volts. Connect it to....
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This is an area that is dominated by commercial information resellers. One outstanding exception is Nostalgia Air, which has a growing data base of radio schematics. Some of the links here point to Nostalgia Air `s database, but if you can`t find it here,....
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This is schematic of a synthesized PLL for the Low Power FM transmitter. By the way, you also can use it with other circuits, just pay attention to recalculate the loop filter response and components, VCO tank circuit, and the correct thumbswitch programming....
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A low power fm pirate radio. The output power is around +35 dBm ( 3. 16 watts) over 50 ohms load and +24 volts power supply. The project consists in a hartley oscillator ( modulated VCO), and tree stages ( Class A, common emitter) of RF amplifiers. The first....
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Here is probably the best ignition coil driver circuit that I have seen. As far as I know it was designed by Jochen Kronjaeger. You can find the original at Jochen`s High Voltage Page This circuit is designed to run from 230V, but I have came up with a....
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IC4, MAX232, is used to connect to the PC by serial port. This connection is useful for debugging and controlling the robot by issuing the command through the keyboard of the PC. Though in real autonomous run of the robot, this connection would be taken off.....
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The FDK Multi-750e was launched in the UK in 1981. A 2m ham radio multimode tranceiver, at a good price, and with a matching 70cm transvertor controlled from the front panel. There are still a good number around, but many have stopped working because of a....
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DX TV enthusiasts often have to deal with relatively crowded VHF bands. In these instances, reduced TV receiver bandwidth results in greater selectivity. The other advantage of bandwidth reduction is improved signal to noise ratio. This results in less noise....
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The setting of delay timing of program will depend on CPU speed. You can use the timing delay on C+ library so you can set the standard timing at any computer but the minimun time delay can achieved was 1ms. It can be improved at less than milisecond by....
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Communication with the MCP3028 ADC chip is done using a simple serial interface compatible with the SPI protocol. The Pic16f84 or Pic16f628 didn`t had hardware SPI peripheral. However, software implemeted SPI protocol can be done to communicate with 12 bit....
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The phone system use to be operated by human operator in a telephone exchange room. The caller will pick up the phone, giving instruction to the operator to connect their line to the destination over the other end of the telephone. As more and more people....
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Chipmunk BASIC has lots off useful functions. So I wrote a small BASIC file to read the serial port and then plot the value on screen (Avaliable upon request FREE). The desktop 386SX PC has a 1. 44 FD and a 40M HD, a VGA with 256k of VRAM. BIOS was configure....
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Tesla coils are air-core, resonant transformers. Working at high frequencies, they can generate tremendous voltages with spectacular lightning-like discharges. The most popular use for them has been in the film industry, where they are used whenever....
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When the 36 kHz infrared light from the LEDs is reflected by an object, one of the receiver modules will be triggered, and the PIC16F84 µController will steer the ROBOT away from the objects by reversing one of the motors...
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A reasonably effective bfo (bifilar oscillator). Its performance is not comparable to more advanced commercial products, of course, but it still works. Anyway, during WWII metal detectors based on the same principle were utilized my combat engineers of many....
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Before examining the various analog to d igital (A-D) and digital to analog (D-A) conversion processes it is useful to review the properties of each type of representation; in particular this may help select the representation most suited to the problem at....
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The objective of this project is to build an Arduino voice shield to empower thousands of voice related applications! All this mostly thanks to an integrated ISD1790PY chip. This particular voice/ TTS feature can be useful to integrate voice messages in....
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The TV transmitter we present today generates a stream containing four TV programs and broadcasts it on a frequency in the DTT standard. Ideal for stacking in an antenna system, audiovisual channels generated on-site or from other sources like a decoder for....
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