Top Circuits Page 270
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This is a Eurocard communications board for TDS2020F or TDS9092 computers (or earlier types). It contains an IEEE-488 Talker/Listener interface and two RS232 ports with all baud rates from 75 to 38400. A DIP switch on the board selects the IEEE address. The....
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This is a CMOS-compatible (and hopefully also TTL) input featuring over- and under-volatage protection. Schmitt triggers are used to allow for input with long transition times. Verified to work up to 30MHz...
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The counter makes use of 5 cascaded CD40110 which combine a decade counter, a display latch and a 7 segment LED driver in a single chip. (The decimal points are driven by IC8x. ) The counter allows up and down counting (although only up counting is used in....
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The divider design is pretty self-explanatory. One can choose between division by 1, 10 or 100 or no output (tied low) using the CONTROL input connected to the analog multiplexer HC4052. AC04are used to drive 3 indication LEDs as well as to buffer the....
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This is basically 4 nearly identical debounced switches. The 2 resistors and one capacity at the input of each Schmitt trigger are used for debouncing the switches. The output is then fed into a D-type flip-flop which uses feedback to change the state (LOW....
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The master mode selection switch is IC6 which switches the 4 mode LEDs (which also correspond to the measured unity, i. e. kHz, counts, milli-seconds or seconds) as well as the input for the divider and the counter : For standard frequency counter mode....
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The lower schematic is a pretty standard bidirectional rectifier together with capacitors and a 7805 as a fixed 5V source which supplies all the electronic in the frequency counter. For "security reasons" a fuse is used. The upper diagram shows the main....
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The oscillator provides a 1MHz and a 1khz clock. The 1MHz clock is used as the clock for the microcontroller and as timebase for millisecond measurement. I use a 2MHz and divide it by 2 in order to guarantee a 50% duty cycle. Then three halve HC390 are used....
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This circuit is a dual low/floating/high logic state detector which enables you to see the logic state of a digital signal pin. Each detector has two LEDs (typically a red and a green one) which indicate the state: red LED for high state, green LED for low....
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The analog input is first fed into a fast non-inverting buffer amplifier (OPA353) set up for unity gain which protects the analog-to-digital converter from out-of-range voltages. The ADS830 is a fairly cheap 8-bit analog-to-digital converter which supports....
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Produce the varying sampling clock write strobe pulses. So, I settled with this semi-optimal but working design applying an ATtiny2313 microcontroller from Atmel. For a 10MHz sampling clock, I need a 20MHz clock for the ATtiny2313and hence it needs to be....
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The digital input board has 8 distinct digital inputs available on JP1. There are separate pull-down resistors (RN1, choose a value you like, e. g. 1MOhm) and then each input has a Schmitt-trigger. Since these may be destroyed by improper input voltages, I....
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The two input boards ( ADCV or digital ) get connected to AD_CTL1, AD_DATA1, AD_SUP5V_1, AD_SUP3V3_1 for the first board and the same names with suffix 2 for the second board. To transfer the sampling data, the 16 digital data lines from the two input boards....
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The device presented here can generate a complementary clock signal at frequencies of 10Hz to 10MHz in steps of factor10. Thus, I chose to call it "10xHz clock generator" (with x being a number between 1 and 7). It can also be used to manually create clock....
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The circuit is a fairly easy design: It consists of the actual VCO (ICL8038 with supplement parts), the sine and triangle output stage (LT1210) and the CMOS-compatible output stage using the MOSFET driver chip ICL7667. The ICL8038 and all parts around on the....
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This is a small footprint 50% duty cycle square wave oscillator with variable frequency from 10kHz to 30MHz. The frequency range can be extended to 1kHz by using 1M instead of 100k for R6. The sheet presented here drives the square wave directly into 50Ohm;....
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The applied microcontroller is an ATMega8 clocked at 16MHz. This microcontoller can shift out arbitrary wavefroms from its flash or SRAM storage at a rate of 2MS/s (and even faster!). The 8bit data is fed from portD to the AD converter ( Analog `s AD7524)....
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In order to programm devices which run at 3. 3V (either SPI-based ones like AVRs or JTAG-based ones like CPLDs), the input and output signal levels need appropriate level conversion (or level shifting) because a 5V input may not see HIGH at 3. 3V and a 3. 3V....
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The goal was to make a small USB interface board which could easily be connected to microcontroller boards. It should support USB-powered as well as externally-powered operation. External components are kept at a minimum (but there are still quite a lot of....
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The goal is to freeze different stages of some fairly quick process (at least when compared to the time resulotion of the human eye). Since I don`t have fancy toys like a high speed film camera, lack of good equipment has to be compensated with a smart setup....
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The goal is to take photos of some fairly quick process (well, at least too quick for the human eye) at exactly specified times with sub-millisecond accuracy. Of couse, with expensive special equipment at hand (such as a high speed camera), this is a trivial....
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Voicemail capacility (although not implemented, there are four ADCs that can be used to sample and record the phone audio) A storage volume (SD card) would need to be connected. This project was inspired by these other homemade exchanges: Markus Wandel and....
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The signal has three wires: common, "walk", and "don`t walk". This page describes the operation of the unit`s countdown feature. The information and examples provided here should work for other models and brands of signals. Click here togo to the beginning....
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For a while I have wanted to add a facility for hazard flashers to my Bonneville SE. I have read a couple of threads on this forum about the subject but not found anything which works like hazards should. I have therefore devised my own add-on system, which....
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The Haynes manuals is extremely confusing regarding the labeling of the relays on Spitfires. The two ways they confuse readers is 1. the illustrations show right hand drive cars with different locations for relays, and 2. the naming of the relays is strange....
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A vacuum fluorescent display (VFD) tube is a type of tube which consists of a hot cathode (filaments), anodes (phosphor) under a high vacuum condition in a glass envelope. This clock uses tube types 8843 or 8894 made by Sylvania in the early seventies. The....
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Numitrons are neat display devices similar to Nixie tubes, but they were designed for low voltage use. Numitrons are basically incandescent displays, using filaments for the segments. Basically, a seven-segment readout consists of seven narrow illuminated....
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Build a CD47 Nixie Clock. Power: approx. 100 Watts (some might say "Isn`t it over- engineered", but you`ll see at the end of that project, that it`s ok. Nixies will be switched off when nobody is around- this will keep them alive as long as possible. The....
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I took 22 used, octal, 6. 3-volt, 600mA, controlled-warm-up tubes (mostly 6SN7s) and 22 octal tube sockets and an old extension cord and wired all the sockets in series. Then I plugged the series into a wall socket and reveled in the soft glow of 22 tubes....
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Considering that I had complained of a schematic typo from Siliconix, it is doubly embarrassing that that April 29`s blog held a few schematic typos of my own creation: in the variation on Morgan Jones`s circuit one of the resistor`s values was off by a....
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Buffers belong in a subset of amplifiers, in general. In addition, power buffers can be thought of as belonging to a subset of power amplifiers, in specific. (Isn`t taxonomy fun ) The uniting features for all buffers are unity gain and a low impedance output....
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The solid-state, unity-gain power buffer is easy to imagine, as many already exist. But what about corresponding tube equivalents Have they been made Could one be made Actually, super cathode followers (complex-and-augmented cathode followers with a gain of....
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With only four transistors and four resistors, the diamond buffer does not require much. Some harsh critics would add that it does not deliver much either. I have covered the circuit and its modification here before, for example in Blog 232 and Blog 187. But....
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Your HVsupply will work, but for your own safety and to avoid accidental damage to your circuit if the event you need to troubleshoot with a scope, I strongly encourage the use of an isolation transformer on the 120VAC input. Just a little 1:1 transformer,....
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A regenerative radio receiver is unsurpassed in comparable simplicity, weak signal reception, inherent noise-limiting and agc action and, freedom from overloading and spurious responses. The regenerative radio receiver or, even super-regenerative radio....
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The Command radio is a description of the radio function, rather than a specific model. The "Command" function was to communicate between aircraft. The "Liaison" function was to communicate back to base. However, functions often become blurred in use, and....
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The LCD display on my NAD C520 compact disk player has become unreadable. The audio and CD deck are operating fine but operating the unit without a legible displayis difficult. If you look at the LCD under the right external lighting you can see that the....
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The Colpitts circuit, like other LC oscillators, consists of a gain device (such as a bipolar junction transistor, field effect transistor, operational amplifier, or vacuum tube ) with its output connected to its input in a feedback loop containing a....
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Low Voltage Differential Signaling (LVDS) interface is a digital video signal transmission vehicle of the most effective interface, it is to send digital audio data stream of low-cost program. This article describes how the use of Maxim Integrated Products....
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Ultrasonic Cleaning the main role in the use of ultrasonic cavitation. Role in the sound field, there is liquid in the bubble will have high-frequency micro-vibration, when the sound pressure reaches a certain value, the rapid growth of air bubbles and then....
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Ethernet has traditionally been a quite complex interface. All Ethernet chips until today had 100 pins or more, where difficult to find in small quantities and difficult to use from a small microcontroller with little memory. Microchip has changed the world....
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This glowing Halloween ghost is available as a kit from the tuxgraphics online shop. It can glow friendly or it can produces scary flashes. You can choose your own face and make a friendly ghost or a scary moster. We wrap a very bright white LED in bubble....
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Your TVT-MOBI-2 will only display this static image and will not yet react to any data received by its serial interface. With one exception. You can set the internal clock of the TVT-MOBI-2 by supplying a date and a time value, and it will calculate the day....
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This web page is provided to offer assistance and information to anyone that is wanting to construct a Tesla coil. I encourage you to make use of the other resources we offer on this page. I live in the United States, and in this country the electrical line....
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How to interface a microcontroller to the phone line. The tones you hear as you enter numbers on your phone can remotely control devices. Learn how to use these DTMF tones in your microcontroller projects. This article was submitted by Mayank Magoo as part....
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DAC is short for Digital to Analog Converter. In this article we play around the code Michael Smith created for a PWM based DAC. I modified his code so that other DAC options could be tried. I compare the 8-Bit PWM DAC with the R2R DAC at various numbers of....
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Built for Birkbeck, the microscope controller is a open source stepper motor driver. It uses an Arduino Uno, and arduino stepper motor shield to drive a Phytron ZSS32. 200 1. 2A 3V stepper motor. To move the sample port, we use an inverted Marzhauser....
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If a linear feedback amplifier contains reactive elements, and at some frequency the loop gain Ab = -1, sinusoidal oscillations will be obtained. The sine wave oscillators investigated in this experiment consist essentially of two separate but connected....
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This was my first AS Electronics project which I built way back in 1998! The original report, with diagrams, is shown here and a PDF version of the report is available for download. There are many occasions where I need to be able to measure small audio....
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A portable CD player, radio, cassette player, a couple of microphones and PC sound card. I am feeding these into the inputs of an audio mixer the output of which is attached to a pair of active loudspeakers. I want to be able to monitor the signal levels....
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After getting some Micro Scalextric for Christmas and shortly after acquiring a vast mount of second-hand track from eBay I decided I needed a lap counter so I could race against the clock with opponents. I didn`t just want to see who could do 10 laps first....
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EncoderBit1(LOW) is negated with the hex inverter U5A and sent to the 4-input AND gate U3A along with EncoderBit0(HIGH), the above J-K output (HIGH), and a HIGH value from Vcc. -During these 5 seconds, the encoder knob is rotated so both bits are set LOW.....
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One of the coolest parts of working on the Yahoo Purple Pedals project was figuring out how we could get the bikes as far off the grid as possible. Once we decided on using the N95 as the brain for the bikes, we had to figure out how much juice it takes to....
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An RF condenser design, it was powered by 12v, supplied to the microphone via the mike cable using a phantom circuit. This is the first known usage of a phantom circuit for microphone powering[1]. Sometime around 1970, Neumann introduced the Fet-80 series of....
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The resistors could be 1/8w, The zener diode could be a 250mW part, or it could be a 1W part (1N number will be different). The electrolytic capacitor is plain vanilla, and the value can deviate (larger is ok, higher voltage is ok), but when it`s all done,....
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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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Most people don`t know it, but there are usually over a dozen, battery backup systems in your home already. The average American around 18 battery backed up devices in their home. These battery backup systems backup the crucial, expensive, or mobile....
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This tutorial shows how you can build a small relay interface board so that you can use the U4x1 devices to control circuits that require more current or a higher voltage than what the U4x1 devices can provide directly. This tutorial is meant to help anyone....
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This program initializes all of the sixteen io lines of the U4x1 to be outputs. The lower four port pins of port A (A. 0 - A. 3) are "channel 1" when it concerns stepper activity, the upper four port pins of port A (A. 4 - A. 7) are "channel 2" when it....
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If you prefer a version that is quicker and easier to build, but which doesn`t have quite the same final appearance I highly recommend the Breadboard Six Transistor Radio Kit. It is also slightly cheaper. This is a MW AM transistor radio which can be....
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This is a very simple ring modulator circuit which will allow you to make interesting analogue sound effects using two audio sources and some kind of amplifier or recording device. Almost everyone has access to a couple of mp3 players and some powered....
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I designed the ZX97 as a discrete copy of the ZX81, which was the first PC for millions of people. In the process ZX97 turned into much more than a mere copy. While it is backward compatible with the ZX81, it is in all other respects a significant....
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Most people who want to modify and improve their Spectrum look first at the keyboard as a prime area for change. But straightforward replacement involves digging around inside the computer - something of a put-off, for two important reasons. To begin with it....
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In order to accomplish this my initial thought is to sample an input (ADC) at consistant time increments and then display the waveform on a graphic lcd display. If I want to change the time scale I can just change the rate of time between samples, and if I....
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Digital Command Control, for those who don`t know, offers many advantages over conventional DC analogue control systems. The main one being the simplicity of wiring. DCC allows one to control many locomotives individually on the layout without having to....
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Metal enclosure, forget the plastic case they sell, it`s nearly useless. ( I made a box from copper PCB that I soldered together, it works okay, but could be better. ) Ground it to the enclosure well, and connect everything to a good earth ground. 4. Make....
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The antenna is simply a pair of vertical dipoles. The diodes in each dipole allows the circuit to select which antenna is active at any given time. When a positive voltage is sent up the coax feedline, diode D1 will conduct and D2 will block, making the left....
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A field strength meter is a very handy tool for locating a transmitter. A sensitive field strength meter by itself has some limitations, however: It will respond to practically any RF signal that enters its input. This property has the effect of limiting the....
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These versions are the original UV-3R, the UV-100, UV-100 MKII, UV-200, UV-200 MKII, UV-3R MKII, UV-3R+, UV-5R, and the UV-5R Plus. KYD (China New Century (Quanzhou) Communication Electronics Co. , Ltd) also sell a version of the UV-100, UV-200, UV-300,....
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After restoring my Fisher 400, I could not let my smart head and creative hands rest. So I have started to look for another tube gear to apply my newly acquired skills. There was plenty of stuff around, but importing from USA to European Union is quite....
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The design is based on the previous analysis of calculating the game in a circular shift register. While designing, it occurred to me that small extensions to the design would enable additional game play features, such as replay and manual input. The final....
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Some serious overengineering was required to match my previous capacitive scanner. At the local hackerspace OSAA I went on to start a brainstorm with pedersen, AsbjG rn and Flemming, who promptly came up with a lot of funnyideas. All nice and well until....
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The aim of this project was to have a bespoke object made using local manufacturing. At the time I was in dire need of a Dub Siren. I found a circuit diagram, with the help of an electronics engineer (Stephan), we drew a schematic, to which he added some....
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This is the 6A schematic that was in the bottom of the unit. It is incorrect. These units have been banging around for over 40 years. Many bottoms have been switched around, due to battery corrosion in the lower case. My Geiger Counter is a 6B, and the....
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Measuring distances using a modulated laser. The circuit I created (see above) is very simple and does not need many explanations. The first part consists of a fixed voltage regulator 7805 to derive a stable +5 V source. This is followed by a LM317....
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I have some Tektronix oscilloscopes with appropriate plug in units yielding an four channel display, I always wanted something else: A true four channel oscilloscope with four distinct X/Y inputs which would allow me not only to display four traces with a....
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The problem with sound cards is that they bandpass their input signals. So, if you are wanting to record any signals below 20Hz or so, you are out of luck, ordinarily. There are two solutions to this problem that I have found. The first, is that if you are....
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The Uno has just sufficient memory and ports. You have to program this one efficient in case you want to store settings in memory etc. Buying the Mega gives you more memory and ports. The Shako valve uses 24 volts DC. I would prefer to use 12 volts because....
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This page will be updated as Material becomes available. This New System will essentially replace the original BCD Design originally designed by WB6IGP and N6IZW and appeared in ARRL UHF/Microwave Project Manual. Their efforts were later revised by WA6CGR.....
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Many versions of VCXO`s this is the final version I have decide to use in all VCXO`s in the Future, it is extremely universal at all Freq. up to 7th Ovetone XTAL`s that can be used in VCXO. NOTE: On this CPLD PLL Board I am using a second Phase Lock....
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This is a Eurocard communications board for TDS2020F or TDS9092 computers (or earlier types). It contains an IEEE-488 Talker/Listener interface and two RS232 ports with all baud rates from 75 to 38400. A DIP switch on the board selects the IEEE address. The....
This is a CMOS-compatible (and hopefully also TTL) input featuring over- and under-volatage protection. Schmitt triggers are used to allow for input with long transition times. Verified to work up to 30MHz...
The counter makes use of 5 cascaded CD40110 which combine a decade counter, a display latch and a 7 segment LED driver in a single chip. (The decimal points are driven by IC8x. ) The counter allows up and down counting (although only up counting is used in....
The divider design is pretty self-explanatory. One can choose between division by 1, 10 or 100 or no output (tied low) using the CONTROL input connected to the analog multiplexer HC4052. AC04are used to drive 3 indication LEDs as well as to buffer the....
This is basically 4 nearly identical debounced switches. The 2 resistors and one capacity at the input of each Schmitt trigger are used for debouncing the switches. The output is then fed into a D-type flip-flop which uses feedback to change the state (LOW....
The master mode selection switch is IC6 which switches the 4 mode LEDs (which also correspond to the measured unity, i. e. kHz, counts, milli-seconds or seconds) as well as the input for the divider and the counter : For standard frequency counter mode....
The lower schematic is a pretty standard bidirectional rectifier together with capacitors and a 7805 as a fixed 5V source which supplies all the electronic in the frequency counter. For "security reasons" a fuse is used. The upper diagram shows the main....
The oscillator provides a 1MHz and a 1khz clock. The 1MHz clock is used as the clock for the microcontroller and as timebase for millisecond measurement. I use a 2MHz and divide it by 2 in order to guarantee a 50% duty cycle. Then three halve HC390 are used....
This circuit is a dual low/floating/high logic state detector which enables you to see the logic state of a digital signal pin. Each detector has two LEDs (typically a red and a green one) which indicate the state: red LED for high state, green LED for low....
The analog input is first fed into a fast non-inverting buffer amplifier (OPA353) set up for unity gain which protects the analog-to-digital converter from out-of-range voltages. The ADS830 is a fairly cheap 8-bit analog-to-digital converter which supports....
Produce the varying sampling clock write strobe pulses. So, I settled with this semi-optimal but working design applying an ATtiny2313 microcontroller from Atmel. For a 10MHz sampling clock, I need a 20MHz clock for the ATtiny2313and hence it needs to be....
The digital input board has 8 distinct digital inputs available on JP1. There are separate pull-down resistors (RN1, choose a value you like, e. g. 1MOhm) and then each input has a Schmitt-trigger. Since these may be destroyed by improper input voltages, I....
The two input boards ( ADCV or digital ) get connected to AD_CTL1, AD_DATA1, AD_SUP5V_1, AD_SUP3V3_1 for the first board and the same names with suffix 2 for the second board. To transfer the sampling data, the 16 digital data lines from the two input boards....
The device presented here can generate a complementary clock signal at frequencies of 10Hz to 10MHz in steps of factor10. Thus, I chose to call it "10xHz clock generator" (with x being a number between 1 and 7). It can also be used to manually create clock....
The circuit is a fairly easy design: It consists of the actual VCO (ICL8038 with supplement parts), the sine and triangle output stage (LT1210) and the CMOS-compatible output stage using the MOSFET driver chip ICL7667. The ICL8038 and all parts around on the....
This is a small footprint 50% duty cycle square wave oscillator with variable frequency from 10kHz to 30MHz. The frequency range can be extended to 1kHz by using 1M instead of 100k for R6. The sheet presented here drives the square wave directly into 50Ohm;....
The applied microcontroller is an ATMega8 clocked at 16MHz. This microcontoller can shift out arbitrary wavefroms from its flash or SRAM storage at a rate of 2MS/s (and even faster!). The 8bit data is fed from portD to the AD converter ( Analog `s AD7524)....
In order to programm devices which run at 3. 3V (either SPI-based ones like AVRs or JTAG-based ones like CPLDs), the input and output signal levels need appropriate level conversion (or level shifting) because a 5V input may not see HIGH at 3. 3V and a 3. 3V....
The goal was to make a small USB interface board which could easily be connected to microcontroller boards. It should support USB-powered as well as externally-powered operation. External components are kept at a minimum (but there are still quite a lot of....
The goal is to freeze different stages of some fairly quick process (at least when compared to the time resulotion of the human eye). Since I don`t have fancy toys like a high speed film camera, lack of good equipment has to be compensated with a smart setup....
The goal is to take photos of some fairly quick process (well, at least too quick for the human eye) at exactly specified times with sub-millisecond accuracy. Of couse, with expensive special equipment at hand (such as a high speed camera), this is a trivial....
Voicemail capacility (although not implemented, there are four ADCs that can be used to sample and record the phone audio) A storage volume (SD card) would need to be connected. This project was inspired by these other homemade exchanges: Markus Wandel and....
The signal has three wires: common, "walk", and "don`t walk". This page describes the operation of the unit`s countdown feature. The information and examples provided here should work for other models and brands of signals. Click here togo to the beginning....
For a while I have wanted to add a facility for hazard flashers to my Bonneville SE. I have read a couple of threads on this forum about the subject but not found anything which works like hazards should. I have therefore devised my own add-on system, which....
The Haynes manuals is extremely confusing regarding the labeling of the relays on Spitfires. The two ways they confuse readers is 1. the illustrations show right hand drive cars with different locations for relays, and 2. the naming of the relays is strange....
A vacuum fluorescent display (VFD) tube is a type of tube which consists of a hot cathode (filaments), anodes (phosphor) under a high vacuum condition in a glass envelope. This clock uses tube types 8843 or 8894 made by Sylvania in the early seventies. The....
Numitrons are neat display devices similar to Nixie tubes, but they were designed for low voltage use. Numitrons are basically incandescent displays, using filaments for the segments. Basically, a seven-segment readout consists of seven narrow illuminated....
Build a CD47 Nixie Clock. Power: approx. 100 Watts (some might say "Isn`t it over- engineered", but you`ll see at the end of that project, that it`s ok. Nixies will be switched off when nobody is around- this will keep them alive as long as possible. The....
I took 22 used, octal, 6. 3-volt, 600mA, controlled-warm-up tubes (mostly 6SN7s) and 22 octal tube sockets and an old extension cord and wired all the sockets in series. Then I plugged the series into a wall socket and reveled in the soft glow of 22 tubes....
Considering that I had complained of a schematic typo from Siliconix, it is doubly embarrassing that that April 29`s blog held a few schematic typos of my own creation: in the variation on Morgan Jones`s circuit one of the resistor`s values was off by a....
Buffers belong in a subset of amplifiers, in general. In addition, power buffers can be thought of as belonging to a subset of power amplifiers, in specific. (Isn`t taxonomy fun ) The uniting features for all buffers are unity gain and a low impedance output....
The solid-state, unity-gain power buffer is easy to imagine, as many already exist. But what about corresponding tube equivalents Have they been made Could one be made Actually, super cathode followers (complex-and-augmented cathode followers with a gain of....
With only four transistors and four resistors, the diamond buffer does not require much. Some harsh critics would add that it does not deliver much either. I have covered the circuit and its modification here before, for example in Blog 232 and Blog 187. But....
Your HVsupply will work, but for your own safety and to avoid accidental damage to your circuit if the event you need to troubleshoot with a scope, I strongly encourage the use of an isolation transformer on the 120VAC input. Just a little 1:1 transformer,....
A regenerative radio receiver is unsurpassed in comparable simplicity, weak signal reception, inherent noise-limiting and agc action and, freedom from overloading and spurious responses. The regenerative radio receiver or, even super-regenerative radio....
The Command radio is a description of the radio function, rather than a specific model. The "Command" function was to communicate between aircraft. The "Liaison" function was to communicate back to base. However, functions often become blurred in use, and....
The LCD display on my NAD C520 compact disk player has become unreadable. The audio and CD deck are operating fine but operating the unit without a legible displayis difficult. If you look at the LCD under the right external lighting you can see that the....
The Colpitts circuit, like other LC oscillators, consists of a gain device (such as a bipolar junction transistor, field effect transistor, operational amplifier, or vacuum tube ) with its output connected to its input in a feedback loop containing a....
Low Voltage Differential Signaling (LVDS) interface is a digital video signal transmission vehicle of the most effective interface, it is to send digital audio data stream of low-cost program. This article describes how the use of Maxim Integrated Products....
Ultrasonic Cleaning the main role in the use of ultrasonic cavitation. Role in the sound field, there is liquid in the bubble will have high-frequency micro-vibration, when the sound pressure reaches a certain value, the rapid growth of air bubbles and then....
Ethernet has traditionally been a quite complex interface. All Ethernet chips until today had 100 pins or more, where difficult to find in small quantities and difficult to use from a small microcontroller with little memory. Microchip has changed the world....
This glowing Halloween ghost is available as a kit from the tuxgraphics online shop. It can glow friendly or it can produces scary flashes. You can choose your own face and make a friendly ghost or a scary moster. We wrap a very bright white LED in bubble....
Your TVT-MOBI-2 will only display this static image and will not yet react to any data received by its serial interface. With one exception. You can set the internal clock of the TVT-MOBI-2 by supplying a date and a time value, and it will calculate the day....
This web page is provided to offer assistance and information to anyone that is wanting to construct a Tesla coil. I encourage you to make use of the other resources we offer on this page. I live in the United States, and in this country the electrical line....
How to interface a microcontroller to the phone line. The tones you hear as you enter numbers on your phone can remotely control devices. Learn how to use these DTMF tones in your microcontroller projects. This article was submitted by Mayank Magoo as part....
DAC is short for Digital to Analog Converter. In this article we play around the code Michael Smith created for a PWM based DAC. I modified his code so that other DAC options could be tried. I compare the 8-Bit PWM DAC with the R2R DAC at various numbers of....
Built for Birkbeck, the microscope controller is a open source stepper motor driver. It uses an Arduino Uno, and arduino stepper motor shield to drive a Phytron ZSS32. 200 1. 2A 3V stepper motor. To move the sample port, we use an inverted Marzhauser....
If a linear feedback amplifier contains reactive elements, and at some frequency the loop gain Ab = -1, sinusoidal oscillations will be obtained. The sine wave oscillators investigated in this experiment consist essentially of two separate but connected....
This was my first AS Electronics project which I built way back in 1998! The original report, with diagrams, is shown here and a PDF version of the report is available for download. There are many occasions where I need to be able to measure small audio....
A portable CD player, radio, cassette player, a couple of microphones and PC sound card. I am feeding these into the inputs of an audio mixer the output of which is attached to a pair of active loudspeakers. I want to be able to monitor the signal levels....
After getting some Micro Scalextric for Christmas and shortly after acquiring a vast mount of second-hand track from eBay I decided I needed a lap counter so I could race against the clock with opponents. I didn`t just want to see who could do 10 laps first....
One of the coolest parts of working on the Yahoo Purple Pedals project was figuring out how we could get the bikes as far off the grid as possible. Once we decided on using the N95 as the brain for the bikes, we had to figure out how much juice it takes to....
An RF condenser design, it was powered by 12v, supplied to the microphone via the mike cable using a phantom circuit. This is the first known usage of a phantom circuit for microphone powering[1]. Sometime around 1970, Neumann introduced the Fet-80 series of....
The resistors could be 1/8w, The zener diode could be a 250mW part, or it could be a 1W part (1N number will be different). The electrolytic capacitor is plain vanilla, and the value can deviate (larger is ok, higher voltage is ok), but when it`s all done,....
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.....
Most people don`t know it, but there are usually over a dozen, battery backup systems in your home already. The average American around 18 battery backed up devices in their home. These battery backup systems backup the crucial, expensive, or mobile....
This tutorial shows how you can build a small relay interface board so that you can use the U4x1 devices to control circuits that require more current or a higher voltage than what the U4x1 devices can provide directly. This tutorial is meant to help anyone....
This program initializes all of the sixteen io lines of the U4x1 to be outputs. The lower four port pins of port A (A. 0 - A. 3) are "channel 1" when it concerns stepper activity, the upper four port pins of port A (A. 4 - A. 7) are "channel 2" when it....
If you prefer a version that is quicker and easier to build, but which doesn`t have quite the same final appearance I highly recommend the Breadboard Six Transistor Radio Kit. It is also slightly cheaper. This is a MW AM transistor radio which can be....
This is a very simple ring modulator circuit which will allow you to make interesting analogue sound effects using two audio sources and some kind of amplifier or recording device. Almost everyone has access to a couple of mp3 players and some powered....
I designed the ZX97 as a discrete copy of the ZX81, which was the first PC for millions of people. In the process ZX97 turned into much more than a mere copy. While it is backward compatible with the ZX81, it is in all other respects a significant....
Most people who want to modify and improve their Spectrum look first at the keyboard as a prime area for change. But straightforward replacement involves digging around inside the computer - something of a put-off, for two important reasons. To begin with it....
In order to accomplish this my initial thought is to sample an input (ADC) at consistant time increments and then display the waveform on a graphic lcd display. If I want to change the time scale I can just change the rate of time between samples, and if I....
Digital Command Control, for those who don`t know, offers many advantages over conventional DC analogue control systems. The main one being the simplicity of wiring. DCC allows one to control many locomotives individually on the layout without having to....
Metal enclosure, forget the plastic case they sell, it`s nearly useless. ( I made a box from copper PCB that I soldered together, it works okay, but could be better. ) Ground it to the enclosure well, and connect everything to a good earth ground. 4. Make....
The antenna is simply a pair of vertical dipoles. The diodes in each dipole allows the circuit to select which antenna is active at any given time. When a positive voltage is sent up the coax feedline, diode D1 will conduct and D2 will block, making the left....
A field strength meter is a very handy tool for locating a transmitter. A sensitive field strength meter by itself has some limitations, however: It will respond to practically any RF signal that enters its input. This property has the effect of limiting the....
These versions are the original UV-3R, the UV-100, UV-100 MKII, UV-200, UV-200 MKII, UV-3R MKII, UV-3R+, UV-5R, and the UV-5R Plus. KYD (China New Century (Quanzhou) Communication Electronics Co. , Ltd) also sell a version of the UV-100, UV-200, UV-300,....
After restoring my Fisher 400, I could not let my smart head and creative hands rest. So I have started to look for another tube gear to apply my newly acquired skills. There was plenty of stuff around, but importing from USA to European Union is quite....
The design is based on the previous analysis of calculating the game in a circular shift register. While designing, it occurred to me that small extensions to the design would enable additional game play features, such as replay and manual input. The final....
Some serious overengineering was required to match my previous capacitive scanner. At the local hackerspace OSAA I went on to start a brainstorm with pedersen, AsbjG rn and Flemming, who promptly came up with a lot of funnyideas. All nice and well until....
The aim of this project was to have a bespoke object made using local manufacturing. At the time I was in dire need of a Dub Siren. I found a circuit diagram, with the help of an electronics engineer (Stephan), we drew a schematic, to which he added some....
This is the 6A schematic that was in the bottom of the unit. It is incorrect. These units have been banging around for over 40 years. Many bottoms have been switched around, due to battery corrosion in the lower case. My Geiger Counter is a 6B, and the....
Measuring distances using a modulated laser. The circuit I created (see above) is very simple and does not need many explanations. The first part consists of a fixed voltage regulator 7805 to derive a stable +5 V source. This is followed by a LM317....
I have some Tektronix oscilloscopes with appropriate plug in units yielding an four channel display, I always wanted something else: A true four channel oscilloscope with four distinct X/Y inputs which would allow me not only to display four traces with a....
The problem with sound cards is that they bandpass their input signals. So, if you are wanting to record any signals below 20Hz or so, you are out of luck, ordinarily. There are two solutions to this problem that I have found. The first, is that if you are....
The Uno has just sufficient memory and ports. You have to program this one efficient in case you want to store settings in memory etc. Buying the Mega gives you more memory and ports. The Shako valve uses 24 volts DC. I would prefer to use 12 volts because....
This page will be updated as Material becomes available. This New System will essentially replace the original BCD Design originally designed by WB6IGP and N6IZW and appeared in ARRL UHF/Microwave Project Manual. Their efforts were later revised by WA6CGR.....
Many versions of VCXO`s this is the final version I have decide to use in all VCXO`s in the Future, it is extremely universal at all Freq. up to 7th Ovetone XTAL`s that can be used in VCXO. NOTE: On this CPLD PLL Board I am using a second Phase Lock....
