Circuit translates a law to m law - 05/07/98 EDN Design Ideas: (NOTE: contains several ideas, scroll down) Two common methods exist to compand voice for transmission through a PCM channel. in Europe, A law involves converting a 12-bit input signal to an 8-bit encoded output. in the US, m law involves encoding 13 bits to 8 bits. You can use a translator to convert from A law to m law (Figure 1). The converter is asynchronous and requires only an 8-bit A law input to provide an 8-bit m law output. Design by Rolando Herrero, Instituto Tecnológico de Buenos Aires, Argentina
Circuitry for Signal Conditioning and Power Conversion - Linear Technology AN75 __ Designed by Jim Williams - Mar 1st, 1999
Circuits adds Programmability to Sensor Amplifier - 03/21/02 EDN Design Ideas: The pressure-sensor amplifier circuit of Figure 1 offers a number of advantages over the traditional approach using the classic three-op-amp instrumentation amplifier. The circuit can operate from a single supply and uses only two op amps and 1% resistors. if the reference voltage, VREF, is 0V, the transducer gain for the circuit isTo ensure equal gain for the two ground-referenced volt Design by Chuck Wojslaw, Catalyst Semiconductor, Sunnyvale, CA
Circuits Monitor & balance large lithium-Ion batteries - 09/03/07 EDN Design Ideas: Using a microcontroller's built-in ADC to measure cell voltage and temperature, this lithium-ion cell monitor equalizes the cell voltage and signals alarm conditions Design by Daniel Gomez-Ibanez, Woods Hole Oceanographic Institution, Woods Hole, MA
Circuit's RMS output is linearly proportional to temperature over wide range - it is known that the p-n diode can be the basis of an accurate thermometer for cryogenic temperatures up to about 200°C. A constant current is maintained through the diode and the voltage across it gives an indication of the temperature. The magnitude of the constant current is typically chosen small to minimize diode self heating. The diode voltage falls linearly with temperature making it necessary to have an operational amplifier conditioning circuit for direct readout. Output calibration is achieved using a voltage reference. Design by R.O. Ocaya, University of the Free State, Phuthaditjhaba, South Africa
Cistern Overflow Alert System - The system presented here will electronically monitor cistern (tank that holds water to flush the toilet) overflows that can otherwise cause seepage in the flats below in a multi-storied building. in...__ Electronics Projects for You
Clamping dissipates minimal power - 03/30/00 EDN Design Ideas: The circuit in Figure 1 is a quasi-linear regulator. it functions as a source follower for input voltages greater than a preset level, determined by VR3. For input voltages lower than the preset level, the pass element, Q2, operates. PDF contains multiple circuits, scroll to find the one of interest Design by Carlisle Dolland, Allied Signal Aerospace, Torrance, CA
Classic High-Precision Low Side Current Sense - This configuration is basically a standard non-inverting amplifier. The op amp used must support common-mode operation at the lower rail and the use of a Zero-Drift type (as shown) provides excellent precision. The output of this circuit is referenced to the lower Kelvin contact, which could be ground in a single-supply application. __ Linear Technology/Analog Devices App Note, Mar 31, 2010
Clear Fluid Detector #2 - Using an ultra low power technique, this circuit detects when a clear fluid is inside a piece of clear plastic tubing. it can be used for fluid level control and monitoring. . . Circuit by David Johnson P.E.-October, 2005
Clear Glass Sensor - industrial grade clear glass sensor modules are widely available but not within the reach of an average electronics hobbyist. The simple clear glass sensor circuit can be used for experiment/hobby purposes. The concept is very simple and is based on a home-made sensor unit comprising one high efficiency ultra bright red LED __ Designed by T.K. Hareendran
Clip-on AC Current Indicator Circuit - Several times over the last few years I have received calls from people looking for a simple circuit that would tell them when a sump pump or water well pump motor was running. These people told me that the electrical circuits that turn on and off . . . Hobby Circuit designed by Dave Johnson P.E.-November, 2004
Closed-Caption Decoder - This is a closed-caption decoder with serial output based on a Microchip PIC 16F628A. The internal comparators of the PIC 16F628A are used to implement a peak detector and data slicer __ Designed by The hardware was Richard Ottosen, and the firmware was Eric Smith
Cloud Charge Monitor - The Cloud Charge Monitor is an extremely sensitive device capable of detecting subtle (and not-sosubtle) changes in the accumulated charge overhead. The device consists of a charge-sensing antenna, a 60 Hz notch filter, a self-zeroing integrator, a signal limiter, and a leakage zero adjustment (circuit / schematic design) __ Contact: Charles Wenzel of Wenzel Associates, Inc.
CMOS
IC 1 kHz Audio Oscillator - This circuit consists of a CMOS
square wave oscillator on a frequency of approximately 1 kHz. The RC filter, which has a roll-off frequency of 500 Hz, filters the harmonics, providing a sine-wave output. The oscillator has many uses; sidetone circuits in transmitters and signal injectors for audio tests are just two __ Designed by Peter Parker VK3YE
CMOS
IC Makes Low-Cost Digital Potentiometer - 01/18/96 EDN Design Ideas: A growing trend in the design of electronic equipment is to replace analog knobs used to increase or reduce a continuous signal (such as volume or brightness]with "up" and "down" keys. However, replacing a low-cost analog potentio Design by Jose Carlos Cossio, Santander, Spain
CMOS
Logic Inverter Amplifier characteristics - This chart shows some of the measured characteristics of three different unbuffered CMOS
logic gates, used as voltage amplifiers. . . Circuit by David A. Johnson P.E.-February, 2002
Coax connectors make low-cost test pieces - 06/22/00 EDN Design Ideas: You can readily construct low-cost test pieces using coaxial panel jacks without pc boards or enclosures (Figure 1). Some engineers and technicians occasionally use this construction technique, but the versatility of the technique is not well-known. You can design and construct these low-cost test pieces for a variety of passive circuits using tee, pi, el, or bridged-tee networks. Design by Richard M Kurzrok, RMK Consultants, Queens Village, NY
Cockcroft Walton Diode Voltage Multipliers - These circuits generate high voltages and can cause dangerous shocks! Do not build these devices unless you are experienced and qualified to work on high voltage devices. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Coil Coupled Operation Metal Detector - A Coil Coupled Operation Metal Detector made from readily obtainable components and using an ordinary medium receiver as a detector. __ Designed by © Rev. Thomas Scarborough
Cold Activated Switch - The thermistor used has a resistance of 15k at 25 degrees and 45k at 0 degrees celsius. A suitable bead type thermistor is found in the Maplin catalogue. The 100k pot allows this circuit to trigger over a wide range of temperatures. A slight amount of hysteresis is provided by inclusion of the 270k resistor. This prevents relay chatter when temperature is near the switching threshold of this circuit __ Designed by Andy Collison
Colour Sensor - Colour sensor is an interesting project for hobbyists. The circuit can sense eight colours, i. e. blue, green and red (primary colours) ; magenta, yellow and cyan (secondary colours) ; and black and white. The circuit is based on the fundamentals of optics and digital electronics. The object whose colour is required to be detected should be placed in front of the system. The light rays reflected from the object will fall on the three convex lenses which are fixed in front of the three LDRs. The convex lenses are used to converge light rays. This helps to increase the sensitivity of__
Combination Tachometer, Thermometer & Counter - inspired by the need to measure dc motor speed and detect overheating, this 68HC908KX8 microcontroller-based circuit displays various statistics on six-digit, eight-segment, numeric LEDs. See movies of a thermistor in action as well as a reflective or interrupt-based photosensor counting. __ Contact David Cook
Comparator Detects failed telecomm supplies - 06/22/00 EDN-Design ideas Detects when telecomm power supplys48V output drops below its nominal value, uses an isolated comparator to monitor two48V telecomm supplies ( Design by Richard Markell, Linear Technology Corp, Milpitas, CA
Comparator Detects position of peaks & valleys in a waveform - 05/24/07 EDN Design Ideas: Simple comparator circuit locates peaks and valleys of a waveform in time Design by Marián Štofka, Slovak University of Technology, Bratislava, Slovakia
Comparator uses signal-dependent hysteresis - EDN Design Ideas: March 26, 1998 [ NOTE: FILE
has multiple design, scroll for this one.] Sometimes, you need to distinguish between two voltages, using some hysteresis in the decision. When the levels of the compared signals vary over a wide range (for example, a few orders of magnitude) , the hysteresis width should vary similarly to ensure a constant ratio between hysteresis width and signal level Design by P Krehlik and L Sliwczynski, University of Mining and Metallurgy, Krakow, Poland
Compensate for Four-Wire Sensor Errors - 07/14/11 EDN-Deaign ideas - Measure sensor values and calculate resistance. Resistive pressure sensors that use two resistive elements and four wires are useful in pressure-monitoring applications. When the pressure rises, one resistance rises and the other falls. Accurate measurements with resistive sensors require compensation for losses due to wire resistance, especially when wire lengths are tens of meters. The compensation method in this Design idea relies on the equal resistance of wires: RL1=RL2=RL3=RL4=RL (Figure 1). Design by Septimiu Pop and Ioan Ciascai, Technical University of Cluj Napoca, Cluj Napoca, Romania
Compensate for four-wire sensor errors - Resistive pressure sensors that use two resistive elements and four wires are useful in pressure-monitoring applications. When the pressure rises, one resistance rises and the other falls. Accurate measurements with resistive sensors require compensation for losses due to wire resistance, especially when wire lengths are tens of meters. __ Designed by Septimiu Pop and Ioan Ciascai, Romania
Complete 12V Automotive Undervoltage, Overvoltage & Reverse-Supply Protection - The LTC4365 is a unique solution that elegantly and robustly protects sensitive circuits from unpredictably high or negative supply voltages. The LTC4365 blocks positive voltages as high as 60V and negative voltages as low as –40V. Only voltages in the safe operating supply range are passed along to the load. The only external__ Linear Technology/Analog Devices App Note, Sep 19th 2011
Complete Type K Thermocouple Measurement System (SPI) with Cold Junction Compensation - The LTC2484 is ideal for direct digitization of thermocouples and other low voltage output sensors. The input has a typical offset error of 500nV (2.5μV max) offset drift of 10nV/°C and a noise level of 600nVRMS. The only signal conditioning is a simple surge protection network. in any thermocouple meter, the cold junction __ Linear Technology/Analog Devices App Note, Apr 8th 2010
Complete, Low-Cost, Software Programmable Ohmmeter Measures Micro-Ohms - 12/06/12 EDN Design Ideas: Numerous applications require the measurement of very low resistances, including but not limited to fuse integrity analysis, relay characterization, and superconductor evaluation. There is a wide range of commercially available equipment designed for this task, but these units are prohibitively expensive and cannot be practically integrated into many applications outside the laboratory. Design by Moshe Gerstenhaber and Mark Champion, Analog Devices, Wilmington, MA
Components for Ion Chambers - Radiation Circuits - components used in making an ion chamber __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Computer Voltage & Temperature Monitoring - The LTC2991 is used to monitor system temperatures, voltages and currents. Through the i2C serial interface, the eight monitors can individually measure supply voltages and can be paired for differential measurements of current sense resistors or temperature sensing transistors. Additional measurements include internal temperature __ Linear Technology/Analog Devices App Notes, Sep 7th 2011
Configure a Low-Cost, 9V Battery-Voltage Monitor - 27-Nov-08 EDN Design Ideas: You can configure an inexpensive, 9V battery-voltage monitor Design by Paul C Florian, McKinney, TX
Connection tester for checking solder joints & other connections - A low resistance (0.25 4 ohm) continuity tester for checking soldered joints and connections __ Designed by Andy Collison
Constant Voltage Load Tests Battery Chargers - 04/11/96 EDN Design Ideas: Testing battery-charging circuits on an actual battery can be difficult, because battery voltage changes during the charging cycle. The constant-voltage "load box" circuit in Figure 1 provide as a constant-voltage load for a battery-charger circuit independent of the amount of input current. A constant-voltage load means that the circuit must have a low impedance at all frequencies. The input impedance of this circuit is approximately 0 ohms at dc and 0.5 ohms at all reasonable input frequencies for charger applications. Design by Jon Dutra, Linear Technology Corp, Milpitas, CA
Construction metal imager - 05/15/14 EDN Design Ideas: Build up an image of inductively sensed, hidden metal using the software equivalent of a long time exposure! My design proposal is to use the LDC1000 to build a metal sensing imager for home and office construction. My first idea was switching an array of coils and controlling an indicating LED for each. The cost of even an eight-by-eight array was prohibitive, and would not give a satisfying image. The second idea was to use a solenoid to activate a marker which would travel through the coil center and mark the surface wherever metal was detected. Again, cost would be prohibitive, and while satisfactory on a construction site, a homeowner might object to having their walls marked up. Design by George Mallard
Contactless AC Mains Voltage Detector - This is a CMOS
IC (CD4033) based circuit which can be used to detect presence of AC mains voltage without any electrical contact with the conductor carrying AC current/voltage. Thus it...__ Electronics Projects for You
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