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Digital  / Logic Circuits 
Digital Circuits:   #'s - C       D - G       H - M       N - R       S - T       U - Z

Last Updated on: Saturday, December 30, 2017 02:17 PM

Circuits Designed by Dave Johnson, P.E.

Digital Counter using PedometerThere are many occasions when you may want to count something electronically.  Perhaps it is car traffic on a street or items moving down an assembly line.  It might be the number of times a machine is activated or maybe you want to count the number of . . . Hobby Circuit designed by David A. Johnson P.E.-August, 2008

Digital noise generatorWhen you need to test an audio circuit with broadband noise, this circuit works great.  It uses just three inexpensive C-MOS ICs that generate a series of output pulses whose widths vary randomly.  I included a level control pot . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2000

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Digital Soil Moisture Meter -  A soil moisture meter is used for indicating the water content of a given soil sample.  As crop production requires water at different stages and in different amounts, it is important...__ Electronics Projects for You

Digital Soil Moisture Tester -  Here is a simple and compact digital soil moisture tester to check whether the soil is dry or wet.  It can also be used to check the dryness or wetness of...__ Electronics Projects for You

Digital Speedometer -  This instrument displays the speed of the vehicle in kmph.  An opaque disc is mounted on the spindle attached to the front wheel of the vehicle.  The disc has ten equidistant.__ Electronics Projects for You

Digital speedometer for cars with 7-segment display of speed -  This page describes the digital speedometer I built in 1995 for my Datsun 1200 __ Designed by Martin Pot

Digital Step Attenuators offer Precision & Linearity -  AN-70-004 Application Note__ MiniCircuits.com

Digital Step-Km Counter-Max. Range: 9,950 meters -  This circuit measures the distance covered during a walk.  Hardware is located in a small box slipped in pants' pocket and the display is conceived in the following manner: the leftmost display D2  (the most significant digit) shows 0 to 9 Km.  and its dot is always on to separate Km.  from hm.  The rightmost display D1  (the least significant digit) shows hundreds meters and its dot illuminates after every 50 meters of walking.__ Learning Electronics

Digital Stereo Potentiometer -  in PDF format, text in Finnish

Digital Stop Watch -  Heres a digital stop watch built around timer IC LM555 and 4-digit counter IC with multiplexed 7-segment output drivers  (MM74C926) . IC MM74C926 consists of a 4-digit counter, an internal output latch, npn...__ Electronics Projects for You

Digital Stopwatch -  times up to an hour in tenths of a second__ Contact: P. Townshend EduTek Ltd

Digital Stopwatch 0-60sec -  By using the same circuit of the Digital Stopwatch 0-99sec , we can add an AND gate, and transform the 0 99sec stopwatch to a 0 60sec stopwatch. __ Designed by Koukos Konstantinos, Tsormpatzidis DimitriosAristotle University of Thessaloniki

Digital Stopwatch 0-99sec -  By using the same circuit of the Digital Stopwatch 0-99sec , we can add an AND gate, and transform the 0 99sec stopwatch to a 0 60sec stopwatch. __ Designed by Koukos Konstantinos, Tsormpatzidis DimitriosAristotle University of Thessaloniki

Digital Storage Logic Probe -  It Interfaces to a Win98 PC to give you more flexibility than you ever thought possible.__ SiliconChip

Digital Storage Oscilloscope Adapter -  Yes, it's finally here !.  The DSOA Mk3 has been a long time coming  (many years in fact) , but it was finally published in the October/November 98 issues of EA.  EA October 98 issue cover shot of DSOA Mk3 Here are the basic specs.  

Digital Switching SystE - M -  This circuit can control any one out of 16 devices with the help of two push-to-on switches.  An up/down counter acts as a master-controller for the system.  A visual indication in...__ Electronics Projects for You

Digital sync-tip clamping: a new approach to video-signal conditionin -  10/08/98 EDN-Design Ideas In digital sync-tip clamping, a stand-alone "clamping" ADC (CADC] incorporates the dc-restore function at its input and eliminates the need for external timing strobes.  This technique encompasses a complete front-end architecture, including sync detection and automatic gain control (AGC] and provIdeas __ Circuit Design by Lazar Shifrin, Advanced Imaging Solutions

Digital Tachometer Avoids Analog Vices -  11/10/94 EDN-Design Ideas The digital tachometer in Fig 1a is a component of the digital seek servo loop in Fig 1b.  The loop produces an error signal that causes a motor to follow a sophisticated velocity profile  (Fig 2].  Although you could use an analog t __ Circuit Design by Tan Van Nguyen, IBM SSD Division, San Jose, CA

Digital Tachometer for Your Car -  Compact design features a 4-digit LED display and a bargraph.  It can also provide gearchange indication and drive a rev limiter.__ SiliconChip

Digital Thermometer -  This digital thermometer can measure temperatures up to 150C with an accuracy of +_1C.  The temperature is read on a 1V full scale-deflection  (FSD) moving-coil voltmeter or digital voltmeter.  Operational amplifier IC...__ Electronics Projects for You

Digital Thermometer Sends Data over AC Power Line -  This circuit is intended for precision centigrade temperature measurement, with a transmitter section converting to frequency the sensor's output voltage, which is proportional to the measured temperature.  The output frequency bursts are conveyed into the mains supply cables.  The receiver section counts the bursts coming from mains supply and shows the counting on three 7-segment LED displays.  The least significant digit displays tenths of degree and then a 00.0 to 99.9 C range is obtained.  Transmitter-receiver distance can reach hundred meters, provided both units are connected to the mains supply within the control of the same light-meter.   __ Contact: Flavio Dellepiane, fladello @ tin.it

Digital Thermometer/Thermostat -  It covers the range from -55 C to 1200C and has an over or under temperature alarm and switched outputs for thermostatic control.__ SiliconChip

Digital Thermometer-Cum-Controller -  This standalone digital thermometer controls the temperature of a device according to its requirement.  It also displays the temperature on four 7-segment displays in the range of 55C to +125C.  At...__ Electronics Projects for You

Digital Thermostat with LED Temperature Display -  I needed to replace two old, unreliable thermostats for controlling the heating and cooling for a large garden shed.  Commercial basic digital thermostats are available quite cheaply, but some lack the ability to control heavy loads or have the extra features that I require for saving energy when the door is often left open or to indicate temperature being out of range etc.  I like the PIC18F1320 microcontroller used in my previous project, so decided to use it again in a very similar design to drive three multiplexed LED displays and read the temperature from a Dallas/DS18x20 "1-Wire" digital sensor.   __ Designed by D. Thorpe, 2006

Digital Thumbwheel Switch -  NOTE : Must register on this site __ Designed by Published in Elecktor July/Aug, 2010

Digital Timer Enhancement -  This simple circuit automatically activates or deactivates an electronic device at the time of alarm preset in a clock.  When the alarm rings, the tone burst generated at the terminal of...__ Electronics Projects for You

Digital Timer for Less than $20 -  Just "nick" the timer from an old microwave oven and fit it into a case.  The resulting timer has lots of uses.__ SiliconChip

Digital timer has independent on/off period -  03/28/96 EDN-Design Ideas You can easily implement a long-interval digital timer using the popular 4060 oscillator-divider IC.  However, in repetitive-timer applications, this IC produces equal on and off times.  The circuit in Figure 1 allows you to set different on and off times; the state of the timers Q14 output automatically selects one of two independent RC time constants __ Circuit Design by Sanjay R Chendvankar, Tata Institute of Fundamental Research, Bombay, India

Digital Timer with 7-Segment Display & Pushbuttons -  The original version of xTimer used MAX7219 for driving 7-segment.  This new design uses a cheap CMOS shift register, 4094 for LED interface.  Each 4094 drives a 0.5" 7-segment without the need of limiting resistor.  The left-hand LED is timer function with buzzer alarm output.  The right-hand is for clock display.   __ Designed by Wichit Sirichote

Digital to Analogue Converters for PC Parallel Port -  JDAC and CENT_DAC are both simple Digital to Analogue converter to use with your IBM PC/AT or compatible.  Those circuit are connected to Centronics parallel port and does not affect the normal port usage in any way.  The circuits are transparent to computer, so it is not possible to program to see if those devices are connected or not. __ Designed by Tomi Engdahl

Digital Up / Down Counter with 7-segment display -  REVISED   Really as Simple as you can get and has 4 Displays __ Designed by G.L. Chemelec

Digital Variable Resistor Compensates Voltage Regulator -  9-Jul-09 EDN-Design Ideas A look-up table compensates for temperature drift __ Circuit Design by Jason Andrews, Maxim Integrated Products Inc, Dallas, TX

Digital VGA Switch -  Digital VGA switch for switching between two PC monitors with MAX465 IC.  

Digital Video Processor -  Circuit Only __ Designed by Stephen Edwards

Digital VLF Receiver -  DDS Synthesized VLF Receiver __ Designed by Steve Hagerman

Digital Voice Recorder ISD2560 -  This project is based on ISD2560P IC which allows us to record 60 seconds voice and playback it with very high quality.  As shown in the schematic, we input the voice by using an electret microphone.  If a dynamic microphone is used, R2, R3, R4

Digital Volt & Amp Meter with Temperature Control -  This project was designed and constructed as enhancement to the 0-30V Stabilized Power Supply Project with the DIY electronics hobbyist in mind.  The circuit uses a single PIC Microchip to perform the Voltage, Current and Temperature conversions and display functions.  The PCB Board uses large  __ Designed by RSABear 2008

Digital Voltmeter -  The ICL7107 is a 3 1/2 digit LED A/D convertor.  It contains an internal voltage reference, high isolation analog switches, sequential control logic, and the display drivers.  The auto-zero adjust ensures zero reading for 0 volts input.   __ Contact: IQ Technologies

Digital voltmeter (DVM) -  This multimeter was designed to measure output voltage and current in a PSU, where the current sense shunt resistor is connected in series with load at the negative voltage rail.  It needs only one supply voltage that can be acquired from main PSU.  An additional function of the multimeter is that it can control  (switch on and off) an electric fan used to cool the main heatsink.  The power threshold at which the fan switches on can be adjusted using One Touch Button Setup.

Digital Voltmeter for Your Car -  A PIC microcontroller makes it a snack to build.__ SiliconChip

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Digital or Logic Circuits:  #'s - C       D - G       H - M       N - R       S - T       U - Z

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