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

Last Updated on: Wednesday, June 02, 2021 01:44 PM

Circuits Designed by Dave Johnson, P.E.

 
Audio Frequency 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. . . Circuit by Dave Johnson P.E.-July, 2000

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

Poor Man's TimerOften during testing of certain equipment and components, you would like to keep track of the elapsed time in hours, minutes and seconds.  There are some nice commercial digital timers and counters available for just this sort of application.  However, . . . Hobby Circuit designed by David Johnson P.E.-August, 2008




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

Digital Audio/ Video Input Selector -  Need to connect more than one audio-video  (AV) source to your colour television? Don’t worry, here’s an AV input expander for your TV.  It is inexpensive and easy to construct.  The working...__ Electronics Projects for You

Digital Audio/ Video Switch -  8 channel switch.   __ Designed by Peter Jakab

Digital Automatic Gain Control ACG -  This project is a digital Automatic Gain Control    (AGC) system using a PIC16F876 MCU.  The ability to set the gain level in a circuit and have it control itself is a very useful function.  This circuit is a building block of another project I am working on.  A 30W power amp for either the PCS, iDEN or CDMA frequency bands.  I will settle on one of those frequencies sometime soon.   __ Designed by steevn.geo @ yahoo.com

Digital Bike Tachometer -  This digital DIY tachometer for bikes uses two reed switches to get the speed information of the bicycle.  The reed switches are installed near the rim of the wheel where permanent magnets pass by.  The permanent magnets are attached to the wheelspokes and activate the reed switches everytime they pass by it.  The speed is

Digital Call Sign Annunciator -  In the USA, R/C wireless video hobbyists are required to operate their video transmitters under the FCC Part 97 regulations    (amateur radio) .  The only exceptions are the Part 15 approved systems, but these low power alternatives are rarely used.  Other countries have similar requirements.  Playing by the rules will certainly prevent conflicts with government officials, since they can levy substantial penalties to offenders.  But more importantly, following the rules is the basis of good amateur radio manners.   __ Designed by RC-CAM T. Black

Digital Camera Adaptor You need not be disappointed next time when your digital camera shows low battery indication during a picnic trip.  Just plug this digital camera adaptor into the cigarette lighter outlet of...__ Electronics Projects for You

Digital Camera Subs as a Scope Camera -  12/09/99 EDN-Design Ideas A digital camera can be a handy substitute for an oscilloscope camera for older scopes that cannot output hard copy or digital data.  A digital camera provIdeas instant results and allows you to easily enhance the image and then ad Design by Allen Moore, Redmond, WA

Digital Capacitance Meter -  This is a simple capacitance meter which can measure capacitance value easy.  There are some measurement methods for capacitance, at one time the capacitance was measured with a impedance bridge or a dip meter.   __ Designed by The Electronic Lives Manufacturing-presented Chan

Digital Clock -  On this page, I will introduce the PIC controled circuit which is the heart of Ultra High Accuracy Digital Clock.  For the details of the clock, refer to "Ultra High Accuracy Digital Clock version 2". 
As for PIC, PIC16F873 is used in the relation of the input-output port.  Also, to make a circuit compact, CPLD is used for the peripheral.   __ Designed by Seiichi Inoue

Digital clock based on 74 series logic -  With pleasure the lot of friends of digital clocks that use discernible components, will see this circuit.  It's a clock, with 12hour clue, little simpler in the manufacture from the SamClock.  It�s a designing that became from the friend George Kordogiannis in 1990, which was modified and corrected in enough points by my, until it reach in the current form.  Most completed that uses is TTL, apart from the IC9 until IC13, that is CMOS , that they have the faculty to drive display Common Cathode __ Designed by Sam Gordon

Digital clock that receives & displays the time from the Rugby MSF radio transmission (PIC16F877) -  A digital clock which receives and displays the time from the MSF radio transmission, broadcast from Anthorn, Cumbria  (54°55'N, 3°17'W) .   __ Designed by © Chris Johnson

Digital Clock Timer-PIC16F628 -  This clock timer uses a PIC16F628 microcontroller to display 3 and 1/2 digit time and control an external load.  The clock includes a calendar with leap year and optional daylight savings adjustments.  The timer output can be set from 1 to 59 minutes and manually switched on and off.  The clock also has a correction feature that allows an additional second to be added every so many hours to compensate for a slightly slow running oscillator.  The oscillator uses a common 32.768 KHz watch crystal and the frequency can be adjusted slightly with the 24pF capacitor on the right side of the crystal __ Designed by Bill Bowden

Digital clock using 2 B7971 HUGE NIXIE TUBES, special muxed -  It looks 10 times better in real life, compared to this small and crap gif animation.  I made it just to give the idea about how it display the time 11:28 __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 2 ZM1040 NIXIE TUBES direct driven -  Simple GIF anim of clock in opperation  (19:10) the fading has only 6 levels in gif file sorry, The fading is made using 50 levels of PWM so it looks perfect smooth, in real life. __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 4 ZM1040 NIXIE TUBES mux 2x2 with a PIC16 -  If you want to know more about the electronics in this clock see this page: nixie-clock2x3.htm.   or you can Download Schematic the file: 2x2e __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 6 HUGE LED Displays multiplexed & PIC16 -  I found 8 huge LED 7 segments at a local marked.  so I guess I just had to use them for something usefull hihi. __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 6 NIXIE TUBES multiplexed 1x6 & a PIC16 -  Since I was a kid I have loved the glow of Neon Nixie tubes.  In 2002 it was time to construct a homemade clock !. __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 6 NIXIE TUBES multiplexed 2x3 & a PIC16 -  Staircase box with 6 ZM1172 Nixie tubes, From RightFrom Left;  Better view of the wood, with power off, From RightFrom LeftFront View;  This Nixie Clock as a kit for sale From Claus Urbach Using proffesional made double sided PCB cards __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 6 small LED Displays & pure TTL logic -  This digital clock was one of the first home designed constructions i ever did, I was in school 5th grade.
Uses 7490 and 7493 counters, 7474 LED display decoder drivers, the timebase is crystal osc.  and dividers It can run for a few month before the gain or loss is too big, to set the correct time two small switches select 100hz or 10khz clock instead of the normal 1Hz __ Designed by Thomas Scherrer OZ2CPU

Digital Clock with Alarm using DS1307 -  DS1307 is a hardware realtime clock, which works on I2C protocol.  Better graphics using the same old fashioned alphanumeric LCD  (type HD44780) .  Icons which shows the status for Alarm ON/OFF state, which gives a nice and cute look to the clock.   __ Designed by Ajay Bhargav, ajay_bhargav @ hotmail.com

Digital Clock with Timer & Solar Panel Regulator -  This is a combination digital clock timer and solar panel charge controller used to maintain a deep cycle battery from a solar panel.  The timer output is used to control a 12 volt load for a 32 minute time interval each day.  Start time is set using 9 dip switches and ends 32 minutes later. __ Designed by Bill Bowden

Digital Combination Lock -  A multiple input combination loack using CMOS counter IC's.  Flexibility and code change is allowed by changing output connections.   __ Designed by Andy Collison

Digital combination lock using paIR of CD4 013 CMOS chips -  The Circuit Board is Designed to accept 2 types of Drive transistors.  I Used a 2N3906 in this schematic, but for Higher Current Drive for a Solenoid, You can use Various T0-220 PNP types of transistors.  USE ONLY ONE OR THE OTHER, NOT BOTH.  In the Picture, I just put a Resistor and LED, where the Solenoid should go.   __ Designed by G.L. Chemelec

Digital controller compensates analog controller -  02/19/09  EDN-Design Ideas Combine the simple and robust closed-loop control of the digital CLZD010 with the current-limited high-side gate drive of the analog LM3485 for the best of the digital and analog worlds Design by David Caldwell, Flextek Electronics, Carlsbad, CA

Digital Controller for Christmas Light Shows -  Want one up on your neighbours? Instead of a static Christmas Lights display  (so passe!) now you can have the ultimate in Christmas extravaganzas.  This amazing controller will bring your Christmas lights to life, making them flash, dim up and down, you name it, all in time with your favourite Christmas music.  It's easy to build, easy to connect and, best of all, easy to program!__ SiliconChip

Digital countdown timer may never need battery replacement -  23-Jun-05 EDN-Design Ideas Processor-based timer draws microamps Design by Mark E Buccini, Texas Instruments, Houston, TX

Digital Counter -  A counter whose logical output increments in steps on receiving clock pulses is used for a variety of counting and timing applications.  It is at the heart of digital clock circuitry...__ Electronics Projects for You

Digital Counter using Pedometer -  There 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 current-source is nonvolatile -  02/07/02  EDN-Design Ideas Digitally programmable current sources that feature automatic trimming and retain the setting despite power-down cycles are useful in applications such as RF- and laser-communications drivers.  The circuit in Figure 1, for example, i Design by Stephen Woodward, University of North Carolina, Chapel Hill

Digital Delay Unit for Surround Sound -  The Mitsubishi M65830 Delay IC has been discontinued  (for reasons beyond my comprehension) , and so far a suitable replacement device has not been found.  This means  (of course) that you will be unable to build this delay circuit.  I have left the project in place as reference, and the overall connection schematic is still valid if  (when?) a replacement for the M65830 is located.  The project will be updated at that time.  In the meantime, just ignore the delay circuit __ Designed by Rod Elliott  ESP

Digital Dialer -  This circuit is the up down circuit of the digital counter which used a rotary encoder.  Two sliding switches are incorporated into the rotary encoder.  The timing that each switch closes is shifted.  Because this circuit detects the timing that each switch closes, it judges the clockwise  (CW) or the counterclockwise  (CCW) of the switch, and adds or subtracts a counter __ Designed by Seiichi Inoue

Digital Dice with Numeric Display -  The circuit described here is that of a digital dice with numeric display.  Timer IC 555 wired as an astable multivibrator produces pulses at about 48 kHz rate.  These pulses are...__ Electronics Projects for You

Digital Dimming DALI Ballast for 32w/T8 110V Input -  This reference design is a high efficiency, high power factor, digital dimming electronic ballast designed to drive rapid start fluorescent lamp types.  The design contains an active power factor correction circuit for universal voltage input as well as a ballast control circuit using the IR21592.  The design also includes a PIC16F628 microcontroller and an isolation circuit for connecting to a Digitally Addressable Lighting Interface  (DALI) .  

Digital Dimming DALI Ballast for 36w/T8 220V Input -  This reference design is a high efficiency, high power factor, digital dimming electronic ballast designed to drive rapid start fluorescent lamp types.  The design contains an active power factor correction circuit for universal voltage input as well as a ballast control circuit using the IR21592.  The design also includes a PIC16F628 microcontroller and an isolation circuit for connecting to a Digitally Addressable Lighting Interface  (DALI) .  

Digital Down Conversion theory -  The advent of larger and faster Xilinx FPGA’s has opened up the field of digital signal processing.  The large
array of configurable logic blocks within the FPGA give great flexibility together with speed, once configured the FPGA is not as flexible as a processor but is much faster.  For many DSP applications speed is important especially for the initial processing of the data, after which the data rate reduces and becomes more manageable.   __ Designed by Brent Knoll

Digital Electronic Lock -  The digital lock shown below uses 4 common logic ICs to allow controlling a relay by entering a 4 digit number on a keypad.  The first 4 outputs from the CD4017 decade counter  (pins 3, 2, 4, 7) are gated __ Designed by Bill Bowden

Digital Engine/Race Computer Board -  The objective of this project is to design a high speed digital engine tachometer.  This requires the design and development of a hardware and software solution to monitor the status of an engine in real time.  In addition, information relating to the overall health and systems of the vehicle can be displayed.   __ Designed by Stephen Manley-smanley @ nyx.net

Digital Filter Cleans Up Noisy Data -  03/02/06  EDN-Design Ideas Cleans up data from pressure and temperature sensors Design by Richard Rice, Oconomowoc, WI

Digital Filter Makes Simple Circuit SPICE Eliminator -  04/10/97 EDN-Design Ideas As an alternative to counter- and shift-register-based techniques, you can use a digital filter to eliminate spikes from a signal  (Figure 1a].  This scheme, which feeds the signal into a digital lowpass filter whose output drives  Design by Francois Corthay Dr Sc, Engineering School Wallis, Switzerland

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


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