Top Circuits Page 44
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DAC0832 shown in Figure 27-13 cushion in the form of a single-phase circuit connected with 8086CPU. Since DAC0832 internal 8-bit data input must be set between the CPU and D/A ..
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This is a general purpose serial port infrared receiver. With the help of appropriate software (see below) you can control different functions of your pc from a distance. For example you can control your home cinema settings (volume, play, pause, stop etc),....
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This article is about a software controlled, parallel port-interfacing 8-channel Pulse-Width-Modulated fan controller. I'll admit that the electronic part of it isn't very advanced, but hopefully the idea of "interfacing" might be interesting.
My old....
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This is the latest version of the Improved Infrared Receiver with Status LED which can control any desktop PC with an ordinary remote control. The project comes along with a small PCB in order to save space. It connects to the serial port as stated in the....
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We have developed a powerful yet inexpensive and easy to construct experiment control system. The construction of the system together with the control software is described here. All circuits and software are free to download and use for nonprofit. The....
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Channel Relay Board is a simple and convenient way to interface 8 relays for switching application in your project. Input - 12 VDC @ 336 mA. Output - eight SPDT relay. Relay specification - 5 A @ 230 VAC. Trigger level - 2 ~ 5 VDC. Berg pins for connecting....
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This circuit is an ETHERNET controller I use the PIC18F452 and the mikroC C Compiler. I use also the JAVA SCRIPT information you can get from www.w3school.com I Control 8 outputs throw the WEB and transfer time information also. I use 3 timer and 3 buffers....
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The DS protocol was designed to provide firmware-based bidirectional host-to-slave inter processor communications for situations in which no hardware solution is available and the host and/or the slave in incapable of tending the interface in real time. The....
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The 040904C version of the code has a larger UART receive buffer and supports two pushbuttons that send either and ASCII "R" ($52) or an ASCII carriage Something to keep in mind when using AVR controllers that support 16 bit addressing(specifically, the....
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This section describes an experimental low power, low bandwidth data signaling system that operates at 100 MHz (In the FM broadcast band in the U.S.). Before operating a radio transmitter, find out what kind of transmitter operation, if any, is permitted in....
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Creating a modular, networked, home control system was greatly simplified by using common 4-wire phone cable with stake-on connectors. The cable feeds both power and network signals to the various modules. Each module is made on a single sided circuit board....
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I2C are widely use for to communicate with external peripheral such as port expender, EEPROM, Real Time Clock etc. The Master Synchronous Serial Port (MSSP) module in PIC18 can be used to communicated with I2C peripheral. MSSP module can be configure to work....
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This report deals with the design for a small asynchronous serial data switch. The switch architecture allows 14 serial ports supporting a subset of the RS-232 protocol. The requirements for the switch are discussed. The hardware interfaces are described in....
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Many RS-485 and RS-422 networks require isolation for safety, noise reduction, or ground loop elimination. A conventional circuit is shown in Figure 1. Unfortunately, optocoupler isolation is slow, complicated, and unreliable. Although RTS does not require....
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This circuit represents a Dive computer interface for RS232. Uses the MAX232A...
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Here is a simple technique for measuring frequencies over quite a wide frequency range and with acceptable accuracy limits using a PC. It follows the basic technique of measuring low frequencies, i.e. at low frequency, period is measured for a complete wave....
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Once i had my SX-64 repaired i wanted to do something cool with it. I learned about people who added ethernet interfaces to their C64 and since i had some spare ones of the required ethernet chips, i decided to build the net64 cartridge. See the image above....
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If you want a powerful, free and portable compiler for the AVR you'll end up with gcc. Fortunately, gcc is supporting the AVR cpu for quite some time now and e.g. the WinAVR toolchain for AVR development under windows is based on this compiler. Many people....
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This page describes a cheap and simple yet flexible HDMI to parallel 3.3v interface. This allows to connect most LCDs frames to the beagleboard without any further interface required. I am using this myself with some 7inch 800x480 displays which i am using....
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Face through attendance as the worlds first embedded facial recognition machine, the error rate is less than one hundred thousandth of the rejection rate of less than one perce..
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FM24C256 as shown 27-54 slave interface circuit I2C bus, the address format shown in Table 27-3. A2, Al, AO is set to low (when extended storage capacity, the need to change A2..
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Computer when you run large-scale software or games machine in the heat will increase the temperature inside the machine so that, especially in the hot summer when more obvious...
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8 parallel input/serial output interface circuit as follows: ..
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American Atmel AT89C52 is produced by low-voltage, high-performance CMOS 8-bit microcontroller chip contains 8KB of rewritable program memory and 256B of random access data mem..
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As shown in FIG, D187 is a universal asynchronous receiver transmitter (UART), its RX/TX signal received optocoupler N21, the N22 and N29, so put the RS-485 communication inter..
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The Atmel Flash devices are ideal for developing, since they can be reprogrammed easy and fast. If you need more code space for your application, particularly for developing 89Cxx projects with C language. Atmel offers a broad range of microcontrollers based....
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The MAX6953 from Dallas Maxim is a compact cathode-row display driver that interfaces a microprocessor (like PIC or AVR) to four 5x7 dot matrix LED display trough an I2C compatible serial interface. The chip includes some features that can help us to handle....
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Generic Digital Switches are in-circuit programmable devices made by Lattice Semiconductor that allow pin to pin routing, buffering, and inversion. Perfect for making last minute circuit changes. Don't muck around with the software provided by Lattice, do it....
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Atmel described a simple programmer based on the AT90S1200 (NOT the AT90S1200A) controller in their application note, AVR910 (a modification to use the AT90S2313 is also given below).The circuit is so small and simple, I was able to put two of them together....
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The Lazy Adapter is composed of a 20 pin DIP socket, a 20 pin DIP header, and 6 pin ISP header, and a small phenolic circuit board to hold them all together. The green fiberglass PCB is a Dontronics DT104 SIMSTIC(This plug is in return for a favor.) I am....
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This adaptor lets me program 8 or 20 pin DIP devices using the In-System Programmer (ISP) described in Atmel's AVR910 application note. This circuit provides power and clocks for the part to be programmed and power to the ISP circuit. When programming 8 pin....
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This programmer requires only a basic terminal program capable of uploading an ascii PIC HEX file. It does not matter what operating system or computer (MAC, Win98, XP, Vista, DOS, Linux, etc.) is used to talk to it. All of the software necessary for....
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C1 is a charge pump capacitor*. This works voltage doubler. When TxD is negative voltage, C1 is charged through D7 from GND. If TxD carries out turn-on, since it will become positive voltage, the voltage charged in C1 is raised. The created high voltage is....
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The SCHAER+ programmer is a programmer for PIC18 family from a PC parallel port (LPT). It is derivated from the SCHAER programmer I used to download my projects in PIC1684. The SCHAER+ programmer should be improved to use a USB connection, without any....
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The idea behind this project is to provide some means of loading a program into a PIC that will then be able to program other PICs in a more conventional way. How do you program a PIC to be a programming device without a programmer, and why would you want to....
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The EEprom programmer software supports the following devices 28C16, 28C256, 28C17, 29C256, 28C64. Diode D1 and resistor R1 provide the VDD isolation when programming the 24 pin devices. The jumper J3 must be shorted for 24 pin devices, and open circuit for....
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In the article you will find a description of the universal PIC programmer, which suggested the involvement of Jens Madsen Dyekjar [ http://www.jdm.homepage.dk/newpic.htm ]. Program allows districts PIC12C5XX, 12C67X, 16C55X, 16C61, 16C62X, 16C71, 16C71X,....
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Most of you will certainly already installed on your computer one of the many software tools move freely from hand to hand and is suitable for programming the PIC 16C84. One of the most popular of this kind is the RIR02 of Silicon Studios. The circuit....
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Simple RS-232 ISP programmer for AT89Sx devices. This device is intended for education purposes and for hobbyists. It has been tested with AT89S2051 and AT89S8253 along with USB to serial port converter cable (with PL2303 chip)...
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The circuit does not present particular difficulties for somebody that has a small experience. The two circuits are the himself, with a small difference only in their input, when they have they measure voltage or current and in connection that concern....
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This is a successor of the PIC16C71 4-digit LED f-counter & V-meter. Some hard to find parts used in the previous version, which are out of production for some time, has been omitted. A rather early PIC16C71 has also been replaced by 28-pin device....
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A bit-error-rate (BER) tester is a basic tool for digital-communications measurements. Although many commercial BER testers are available, you can easily design and build an inexpensive version. The scheme in Figure 1 has performance similar to that of a....
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This Field Strength Meter is simple and also quite sensitive. It uses an ordinary digital voltmeter to measure RF signal strength up to a few hundred MHz. The multimeter should be set to the lowest dc volts range for maximum sensitivity. This is normally....
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This is a wide band signal strength meter circuit which responds to small changes in RF energy, designed to be used for the VHF spectrum and will respond to AM or FM modulation or just a plain carrier wave. This circuit measures radio field strength by....
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Large moving-coil meters may require significant amounts of current for full-scale deflection, and using a shunt resistor may prove impractical when the meter current is larger than the current you are measuring. You can solve the problem by driving the....
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This is a simple rev-counter which can measure up to 100,000 rpm with method of strobe synchronization. Its usage is easy. Put a marker on the shaft before measureing, light on the shaft by flashing LED and adjust flashing frequency with the potentiometer as....
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This is an image Schematic. No Description available...
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Many beginners trying out their skill with QRP TX, for the first time have to overcome many problems before they are able to come on the air. On usual complaint is that, every thing is working fine but the signal is not going out. Here is a simple set up....
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When I was recently debugging a design, I discovered that a short circuit existed from a ground plane to a power plane. I did not have access to a milliohmmeter or an equivalent tester for locating this type of short circuit. So, I logged onto the Internet....
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From a high-volume-production point of view of the Design Idea `Test batteries without a voltmeter` (EDN, Nov 9, 2000, pg 167), it is a time-consuming and laborious task to tweak the large number of potentiometers on each of the comparator input references.....
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This circuit is from Tomi Engdahl's page. It describes a nifty little TDR that, when combined with a regular oscilloscope, can be used to find discontinuities on long runs of cables...
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With a few inexpensive components and INT1Ch, you can turn the printer port of your PC into a high-current ammeter. This design`s goal is to make remote high-current measurements, but you can use this technique to remotely measure any other similar analog....
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VU (Volume Unit) meters used to be the mainstay of audio metering systems, but they have been replaced by LED metering in a great many mixers and other applications. Even in software, the most common level meter is made to look like an LED meter. The Peak....
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Using inexpensive components, you can fit a simple probe circuit into a pencil-sized enclosure. When both LEDs are on, the probe indicates the presence of an ac voltage; either LED alone indicates the presence and polarity of a dc voltage. The diode-bridge....
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The spectrum analyzer circuit takes a stereo input and displays a volume by
frequency display on a standard PC monitor. Finding the amplitude of a waveform at
each frequency and then mapping this to the screen using a discrete number of levels
achieve....
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This tiny pH-meter is very tiny: 11cm2 including the PSU circuit! I built it for the College Saint Pierre a few years ago. It is based on a circuit developped at the Facultes Notre-Dame de la Paix, Namur, Belgium. I modified several components to allow a....
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Having found an u664b prescaler chip (Telefunken) from an old tv-tuner , I decided to build a valid frequency counter using pic16f84 , the prescaler I use is able to divide by 64 every frequency from 30 to 1300 MHZ. The original project is from Peter....
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Ammeter is a great addition to any Laboratory Power Supply as it will measure the current consumption and help you determine if there are any problems with the circuit that you are building or testing. This amper meter is capable of measuring the current....
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This circuit will give you a good, Accurate Watt Meter that can measure various power levels.
In the Origional Article the Shunt was a .001 Ohm Copper Shunt giving a 1000 Watt Scale. However, because Most Circuit Breakers in homes are 15 Amps, I made my....
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This circuit is designed to provide an inexpensive way to to create a High Impedance Voltmeter while making use of an inexpensive analog or digital multimeter. When measuring voltages in high resistance circuits the resistance of the voltmeter itself has an....
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The Bray Barometer requires manual calibration for voltage offset and gain. Although practical on the workbench, these devices are most likely mounted in inconvenient locations making secondary adjustment difficult.
The Bray Barometer uses potentiometers....
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No Description available...
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Our CONTINUITY TESTER gives an audible indication of continuity between the probes so you can keep your eyes on the probe tip. Secondly its response-time is very short so that you can make lots of tests very quickly while listening for the beep.
And....
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This project is exactly what you need. It is simple to construct and can be connected to almost any analogue multimeter.
The scales are accurate over each range - certainly good enough to provide you with the value of any capacitor between 1p and 10u.
The....
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Firstly, we will describe the "add-on" version for the 5x7 Display as this is the cheapest version and, quite frankly, it only deserves a few dollars as a piece of test equipment.
It`s "all the rage" to have an Electrolytic Tester for servicing equipment....
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This Field Strength Meter has been specially designed for our FM bugs. It is capable of detecting very low power transmitters and will assist enormously in peaking many of our FM transmitters that have a coil in the output stage that can be adjusted for....
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This project has 3 features.
1. It`s a Field Strength Meter,
2. A Frequency Meter and,
3. An aid for testing detuned transmitters.
Its uses will become clear in a moment but firstly let`s go over the background of a Field Strength Meter.
A Field....
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The LED power Meter is a simple RF detector using diodes to charge a capacitor. The voltage developed across the capacitor is indicated by a multimeter set to a low voltage range. The circuit is soldered together without the need for a PC board, as can be....
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The pre-distortion circuit described here is extremely simple (Figure 1) and only requires one trimmer adjustment, though you`ll need an accurate way to measure THD in order to achieve the best results. A dedicated distortion analyzer to help you adjust the....
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Since the speed of the I2C bus can be rather high, it is recommended to use a fast optocoupler. However, this circuit will not work on speeds higher then 10KHz. A 6N139 will do the job in all cases. The two PNP and the two NPN transistors can be any standard....
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A low resistance ( 0.25 - 4 ohm) continuity tester for checking soldered joints and connections. This simple circuit uses a 741 op-amp in differential mode as a continuity tester. The voltage difference between the non-inverting and inverting inputs is....
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This tester is designed to locate stray electromagnetic (EM) fields. It will easily detect both audio and RF signals up to frequencies of around 100kHz. Note, however that this circuit is NOT a metal detector, but will detect metal wiring if it conducting ac....
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Using a single 555 Timer IC and a small transformer to generate a high voltage, this circuit will test zener diodes of voltage ratings up to 50VDC. The 555 timer is used in the astable mode, the output at pin3 drives a small audio transformer such as the....
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This circuit is not a novelty, but it proved so useful, simple and cheap that it is worth building.
When the positive (Red) probe is connected to a DC positive voltage and the Black probe to the negative, the Red LED will illuminate.
Reversing polarities....
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Ideal to operate 3 to 24V DC existing on-circuit lamps
LED operation is also possible. This circuit was designed to provide that continuous light lamps already wired into a circuit, become flashing. Simply insert the circuit between existing lamp and....
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This simple circuit generates narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes. A high-pitched....
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Measures 10mV to 50Volt RMS in eight ranges.
Simply connect to your Avo-meter set to 50µA range. Connect J2 and J3 to an Avo-meter set to 50µA range. Switching SW2 the four input ranges will be multiplied by 5. Total fsd ranges are: 10mV, 50mV, 100mV,....
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This circuit, designed on request, has proven to be useful to indicate when the voltage in a power supply line is changing from 120V to 240Vac. It can be used in different circumstances and circuits, mainly when an increase in ac or dc supply voltage needs....
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Detects the presence of a live mains conductor.
Minimum parts counting. If the unit is brought close to a live conductor (insulated, and even buried in plaster) capacitive coupling between the live conductor and the probe clocks the counter, and causes the....
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Tests 1.5 to 15 Volt cells. This circuit runs a fast battery test without the need of power supply or expensive moving-coil voltmeters. It features two ranges: when SW1 is set as shown in the circuit diagram, the device can test 3V to 15V batteries. When SW1....
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This is a low power voltmeter circuit that can be used with alternative energy systems that run on 12 and 24 volt batteries. The voltmeter is an expanded scale type that indicates small voltage steps over the 10 to 16 volt range for 12 volt batteries and....
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This circuit is used to measure the voltage on a 12V (nominal) lead acid rechargeable battery system. It was specifically designed for use in solar powered systems, but is general enough that it can be used for automotive or other 12V systems. Lead acid....
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This little instrument identifies faults in horizontal output stages by doing a `ring` test, i.e. it applies pulses to the LOPT / FBT primary circuit, and counts the number of damped oscillations or `rings` produced. For each `ring` down to about 15% of the....
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At some stage, we will all find ourselves pushing hi-fi equipment just a little too hard, and if lucky, will just find that the sound has become "dirty". If this happens too often or is too severe, tweeters are the first to go - they are damaged by the....
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When building amplifiers, it is often necessary to test transistors, either to verify that they (still) work, or for some esoteric designs it may even be necessary to match certain characteristics.
The design featured here is just what you need, and....
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Total harmonic distortion (THD) measurements are one of the most commonly quoted in audio. Contrary to belief in some circles, these can be very useful if performed properly, and reveal much about the overall performance of an amplifier.
There are a....
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Measuring the voltage converter can be set to switch to the right, left AC voltage range selector switch to any one file, then..
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A milliohmmeter is just the tool for checking trace resistance on a printed circuit board, tracking down shorted traces, and measuring the contact resistance of a switch or connector. Its the kind of tool that would come in real handy occasionally, but not....
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As I used this probe last nigh to determine if a 384 MHz oscillator was really working or not, I remembered email I received a while ago, asking how to make a field strength indicator without the microcontroller. Thus this page. If you want the auto zero....
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The "Battery Good" checker. When the button is pressed, the green LED will glow if the battery voltage is above the preset threshold. This version has a higher parts count than the "Battery Low" version, but a bonus is that it can drive an LED to be very....
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The result was a project that includes a waveform capture circuit, a graphic LCD (Liquid Crystal Display) and a control panel with LED indicators. As described, the display plugs directly into the waveform capture and control unit, which is what the what the....
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Here is a handy zener diode tester which tests zener diodes with breakdown voltages extending up to 120 volts. The main advantage of this circuit is that it works with a voltage as low as 6V DC and consumes less than 8 mA current. The circuit can be fitted....
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This is a CMOS IC (CD4033) based circuit which can be used to detect presence of mains AC voltage without any electrical contact with the conductor carrying AC current/voltage. Thus it can be used to detect mains AC voltage without removing the insulation....
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The method goes by the switching method. Making it be possible to see four kinds of the input signals at the same time by switching them at the short period. In addition to the way of introducing here, there is a method which changes the input every period.....
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The tool is based on a NE555 (or LM555) timer i.c., wired as an astable multivibrator. The frequency of the multivibrator is determined by the value of the unknown capacitor Cx. The circuit can be fed by a small battery. I use myself a 9 V block battery....
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Continuity tester to check continuity in the circuit (Insakittochekka) is. The continuity check over the circuit board wiring that can be checked at a lower voltage semiconductors do not conduct contained in the circuit, you can just check the wiring short....
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Simplified logic checker. Logic voltage levels have the ability to display LED (Of course I (^_^;)." H "in the LED is green," L "and red LED lights, and so both the open and goes out .
But not only that was put on the ability to detect narrow pulses. In....
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Photo diode outputs light current that is well proportional to input light power when it is used in short mode. In this lux meter, the output current is converted to voltage with an I-V converter, it is captured by a micrcontroller and displayed it in term....
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This is a portable oscilloscope adapter that it can be held in breast pocket. Its operation is only sampling and sending to host PC. The most of functions of the oscilloscope are processed by host PC. Therefore, oscilloscope adapter can be simplified. This....