Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com, has 45,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.
We make every effort to link to original material posted by the designer. 
Please let us if you would like us to link to or post your design.

HOME Schematics Index Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches



Clock Circuits:   A - B      C - D      E - P      Q - Z


Last Updated: December 07, 2017 02:04 PM


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

Circuits Designed by  Dave Johnson, P.E.

Garage Door Closer -  The circuit below is designed to automatically close a garage door, if it was left open for a long period of time.  A reed relay and magnet combination sense when the door is fully open.  An ultra low power voltage comparator oscillator and two 74HC4040 ICs  are used to generate the time delay . . . Dave Johnson, Lubbock TX (May 14, 2011)-DC Magazine - Issue 18 May 2011

Garage Door Timer  -  The circuit below is designed to automatically close a garage door, if it was left open for a long period of time.  A reed relay and magnet combination sense when the door is fully open.  An ultra low power voltage comparator oscillator and two 74HC4040 ICs  are used to generate the time delay . . . Circuit by Dave Johnson P.E.-May 14, 2011

Laser Used as Vehicular Traffic Counter  -  This is an illustration how a laser could be used to count traffic and measure the speed of each car passing through the sensor area . . . Circuit by David A. Johnson P.E.-July 09, 2006

Line Powered 60hz Clock Generator  -  This circuit is connected to the 120vac power line and transfers 60Hz clock pulses to a logic circuit.  The optoisolator used provides 5000 volts of isolation between the power line and the logic side of the circuit . . . Circuit by Dave Johnson P.E.-June 27, 2000

Long Period Computer Watch Dog Timer  -  This circuit uses a simple 4060 IC oscillator/timer that is reset periodically by a computer.  Should the computer fail to send a pulse, the output changes state.  The time can easily be set from seconds to hours . . . Circuit by David Johnson P.E.-December 26, 1995

Motorized Duck Decoy Timer  -  I received a nice email from a duck hunter.  He uses some motorized decoys to lure ducks into his line of fire.  However, the battery powered decoys only have an on/off switch so once turned on; the decoy flaps its wings or paddles around continuously.  The hunter wanted a more realistic motion, which would power the motor for say 10 seconds, then stop for another 10 seconds before starting up again. The simple circuit below should work well for his application . . . Hobby Circuit designed by David Johnson P.E.-August 30, 2011

On/Off Flip/Flop Circuit with Automatic Timeout  -  This circuit is ideal when a device needs to be turned on and off with a single pushbutton switch, but also needs to turn itself off after some period of time.  With the components shown, the output will stay on for only about 20 seconds . . . Circuit by David A. Johnson P.E.-December 16, 2004

On/off Pushbutton Switch with 30 Minute Timeout  -  I received an email from a Discover Circuits visitor.  He wanted to control power to a LED camping light he was building.  He wanted to turn the light on and off with a small pushbutton switch.  He also wanted a timer so the light would not stay on longer than 30 minutes at a time.  It seems that his kids often turned lights on when going to bed and then forgot to turn them off . . . Circuit by David Johnson P.E.-January 08, 2012

Poor Man's Timer  -  Often 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 Dave Johnson P.E.-August 24, 2008

Pushbutton Activates Service Request Beeper  -  A single press of a pushbutton switch turns on a beeper for one second but can’t be activated again for 60 seconds. . . . Circuit by David A. Johnson P.E.-July 09, 2006

PWM Motor Controller uses a 555 Timer  -  Using a CMOS version of the 555 timer, this circuit can be used to control the speed of a motor by adjusting the duty cycle of the pulses sent to the motor . . . Hobby Circuit designed by David Johnson P.E.-June 30, 2006

Edge detector runs off of single supply  -  12/04/97 EDN Design Ideas:     You can use a single-supply circuit to generate a pulse on both the rising and the falling edges of a signal for use with counters or similar devices that require only a rising edge to trigger (Figure 1a).   R1 and C1  form a differentiator that converts rising edges to positive spikes and falling __ Circuit Design by Joe Meloche, Ingersoll-Rand Fluid Products Division, Bryan, OH

Exclusive 2.5 GHz Frequency Counter with Blue 2x16 LCD display  -  This project explain a very powerful frequency counter which has many useful software functions.  The software can add or subtract 3 different iF frequencies (±455 kHz , ±10.7 MHz and ±21.4 MHz). You have also two level of resolutions, 1kHz and 100Hz. The main oscillator can be on-board 13MHz or external 10 MHz. The counter data can easy be transmitted to computer with RS232 cable (software below) The construction is extremely simple and the unit is very small. This project comes in a KiT version, se more details below. __

Garage Door Closer -  The circuit below is designed to automatically close a garage door, if it was left open for a long period of time.  A reed relay and magnet combination sense when the door is fully open.  An ultra low power voltage comparator oscillator and two 74HC4040 ICs  are used to generate the time delay . . . Dave Johnson, Lubbock TX (May 14, 2011)-DC Magazine - Issue 18 May 2011

Garage Door Timer  -  The circuit below is designed to automatically close a garage door, if it was left open for a long period of time.  A reed relay and magnet combination sense when the door is fully open.  An ultra low power voltage comparator oscillator and two 74HC4040 ICs  are used to generate the time delay . . . Circuit by Dave Johnson P.E.-May 14,2011

Gated clock has duty-cycle control  -  08/17/00 EDN Design Ideas:  The circuit in Figure 1 produces clock pulses with variable duty cycle from a gated clock.  The output of the circuit, pulse, is always 180° out of phase with the clock input.  When the delay-logic elements, IC 5 and IC 7, have the same propagation delays, the duty cycle of the circuit's output is 50%.  The circuit __ Circuit Design by Paul Kemp, University of Colorado, Colorado Springs, CO

Generating Multiple Clock Outputs from the AD9540  -  AN-769 Analog Devices App Note__

 

Giant nixie clock  -  At the beginning of 2001 I had never heard of nixie tubes.  Then I came across Mike's Electric Stuff and saw his Nixie Clock.  Almost instantly I fell in love with nixies  then I had the idea of building a nixie clock and this project was the result. __ Designed by Hans Summers

Hard Drive Clock  -  Have an old hard drive that no longer works? As long as it still spins up chances are you could build a clock out of your old hard drive!  You will need some electronic knowledge, some common electronic components and a bit of patience. The clock that is produced isn’t exactly practical__ Designed by Alan Parekh

Increasing the Number of Outputs from a Clock Source Using Low Jitter LVPECL Fanout Buffers   -  The EVAL-ADF4351EB1Z board uses the standard ADF4351 programming software contained on the CD that accompanies the evaluation board. CiRCUiT EVALUATiON AND TEST, Getting Started The UG-435 user guide details the installation and use of the EVAL-ADF4351EB1Z evaluation software.  Install the ADF435x software to PC by doing the following: __ Analog Devices-Circuits from the Lab

Inverting Level-Shift Circuit Has Negative Potential  -  EDN-Design ideas -- 07/24/12    Shift clock logic levels to match the requirements of the driven device.__  by Chun-Fu Lin and Shir-Kuan Lin, National Chiao Tung University, Hsinchu, Taiwan; and Hui-Shun Huang, Jyi-Jinn Chang, and Tai-Shan Liao, National Applied Research Laboratories, Hsinchu, Taiwan

Keep clocks in line with LVDS replicator  -  01/06/00  EDN Design Ideas:  intended for use in telecommunications and other high-speed data systems, National Semiconductor's DS-92CK16 chip (Picture) allows you to generate multiple copies of clock signals with a channel-to-channel skew of 50 psec.   __ Circuit Design by Graham Prophet

Laser Used as Vehicular Traffic Counter  -  This is an illustration how a laser could be used to count traffic and measure the speed of each car passing through the sensor area . . . Circuit by David A. Johnson P.E.-July 09,2006

LCD Clock/Calendar  -  LCD Display with Date and Time, 12hr format. __ Designed by Jose Pino

LCD Display with Minimum Mass Wireless Coupler  -  its an adaption of the 2X 16 LCD project, by adding a fettite loop antenna, two resistors, and a capacitor. Here the display shows the output of the 10 bit scanning voltmeter with Minimum Mass Wireless Coupler.   (ATtiny2313, AT90S2313) __ Designed by Dick Cappels

LED Clock  -  12Hr LED clock using 16F628. Also, schematic to build a Jumbo clock is included__ Designed by Jose Pino

LED 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. The 32 minute duration is set by selecting the 5th bit (2^5 = 32) of a 4040 binary counter (pin 2). The timer also has a manual toggle switch so the load can be manually switched on or off and automatically shuts off after 32 minutes__ Designed by Bill Bowden

LED matrix clock  -  xxx__ Designed by Hans Summers

Line Powered 60hz Clock Generator  -  This circuit is connected to the 120vac power line and transfers 60Hz clock pulses to a logic circuit.  The optoisolator used provides 5000 volts of isolation between the power line and the logic side of the circuit . . . Circuit by Dave Johnson P.E.-June 27,2000

Long Period Computer Watch Dog Timer  -  This circuit uses a simple 4060 IC oscillator/timer that is reset periodically by a computer.  Should the computer fail to send a pulse, the output changes state.  The time can easily be set from seconds to hours . . . Circuit by David Johnson P.E.-December 26,1995

Low-Power Interrupt Updates Real-Time Clock  -  07/07/94 EDN Design Ideas:  Some µP-based systems need a real-time clock.  The µP's built-in timer can do the work, but it usually requires several milliamps of current to keep the timer running.  If the main power drops, the clock requires a backup battery to operate.  The size of the backup battery __ Circuit Design by Yongping Xia, EBT Inc, Torrance, CA

LTC Design Note: Robust 10MHz reference clock input protection circuit and distributor for RF systems  -  EDN Design Ideas:  07/31/2014     Design a protected 10MHz reference input without degrading phase noise __ Circuit Design by Michel Azarian

LTC Design Note: Uncompromised clocking solution for 16bit 2.5Gsps DAC  -  EDN Design Ideas:  01/30/2017    System performance & phase noise depend on clock as much as DAC quality __ Circuit Design

Lua Railway clock WiFi ESP8266  -  Swiss railway clock is precise digital wifI clock.  It's a miniature web server and very good demo for ESP8266 & Lua fanclub.
By mapping ports of your router, you can connect to it from anywhere on the world. This clock uses Lua software and
trendy vector graphics format SVG with animations. The clock is particularly interesting for its graphic design.  In terms of program, it using
synchronization the time from an external NTP server.  Thanks to this, clock is quite fast and precision, which was my goal.__ Designed by © Pavel Janko

Mains Clock Controller Using AT89C2051.1  -  The Clock Controller V1.1was designed to be an exemplary of using 'C' language to control timer0interrupt, 7-segment LED and keypad scanning.  It provides 1-bit sink currentdriving output, for driving a relay, opto-TRIAC, say. Many projects requiring7-segment display and keypad interfacing may get the idea from the Clockcircuit and software. __ Designed by Wichit Sirichote

Make an Asynchronous Clock for VPX-Based Pcie Systems  -  01/19/12  EDN Design Ideas:  Careful crystal selection and an FPGA are key to success.   __ Circuit Design by Vadim Vaynerman, Bottom Line Technologies Inc, Westminster, MD

Mechanical Wall Clock Quartz Synchronizer  -  The synchronizing circuit that produces a short magnetic pulse to keep the pendulum in near perfect time was made using a crystal oscillator and binary counters to generate a 60mS pulse at the required rate of
53.4241 PPM. I didn't know the exact rate, but it appeared __ Designed by Bill Bowden

Modeller’s Clock  -  The special feature of this analogue wall clock is that it uses a standard model servo to tell the time. The display principle is the same as for an ordinary wall clock, but with two important differences. A standard model servo is unable to cover a travel of 360°, so we’ll need to adapt the clock face to this situationmust register on this site__ Designed by Published in Elecktor July/Augu, 2010

Morse Code Alarm Clock Modification  -  (Almost) Trivial application of an AT90S2313 or ATtiny2313 in an alarm clock to change the alarm from "BEEP BEEP BEEP BEEP BEEP BEEP BEEP BEEP" to "WAKE UP" in Morse code. This was designed in response to a request and is in daily use__ Designed by Dick Cappels

Motorized Duck Decoy Timer  -  I received a nice email from a duck hunter.  He uses some motorized decoys to lure ducks into his line of fire.  However, the battery powered decoys only have an on/off switch so once turned on; the decoy flaps its wings or paddles around continuously.  The hunter wanted a more realistic motion, which would power the motor for say 10 seconds, then stop for another 10 seconds before starting up again. The simple circuit below should work well for his application . . . Hobby Circuit designed by David Johnson P.E.-August 30,2011

Nixie-Clock using Neon Lamps to form Logic Gates  -  The above shows my home-built digital clock.  It uses Nixie-tubes for readout.  In contrast to most other nixie-clocks being built these days, my clock does not use any transistor or IC for driving the tubes.  Instead, the driving logic is built from neon lamps, together with resistors, capacitors and silicon diodes. __  Contact:  pa3fwm @ amsat.org

Nixie-Tube Clock  -  This is a my nixie-tube clock built 8 years ago. __ Designed by The Electronic Lives Manufacturing-presented Chan

On/Off Flip/Flop Circuit with Automatic Timeout  -  This circuit is ideal when a device needs to be turned on and off with a single pushbutton switch, but also needs to turn itself off after some period of time.  With the components shown, the output will stay on for only about 20 seconds . . . Circuit by David A. Johnson P.E.-December 16,2004

On/off Pushbutton Switch with 30 Minute Timeout  -  I received an email from a Discover Circuits visitor.  He wanted to control power to a LED camping light he was building.  He wanted to turn the light on and off with a small pushbutton switch.  He also wanted a timer so the light would not stay on longer than 30 minutes at a time.  It seems that his kids often turned lights on when going to bed and then forgot to turn them off . . . Circuit by David Johnson P.E.-January 08,2012

Oscilloscope CRT Clock  -  Apparently  I'm in the shameful habit of making clocks in my spare time. First it was the Weston voltmeter clock, and then "Nixie 1, " a single-digit Nixie clock. Since soon after finishing the latter, I'vebeen daydreaming about making a clock out of an electrostatic deflection CRT—the kind of thing you find in an oscilloscope. Given that I'vejust come across some free time in the form of Christmas vacation 2005, I decided to make one of my own__ Designed by © 2007 Riad S. Wahby

Pacer clock saves subroutine calls  -  11/10/05 EDN Design Ideas:  Time-delay routine requires no subroutine calls, avoids stack-overflow hazards __ Circuit Design by Enver Torlakovic, Willmot, New South Wales, Australia

PC's parallel port to program a clock source  -  7-Dec-04 EDN Design Ideas:    This design idea shows how you can use Linear Technology's LTC6903 programmable oscillator as a clock source for direct-digital synthesis, data conversion, switched-capacitor filtering, clock, and voltage-controlled oscillator circuits.   The LTC6903 operates from 2.7 to 5.5V with modest power consumption and can produce clock signals at frequencies of 1 kHz to 68 MHz __ Circuit Design by William Grill, Honeywell BRGA, Lenexa, KS

PIC Digital Clock Timer  -  This clock timer uses a PIC 16F628 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

PIC Tock Video Clock  -  PIC -Tock is a video clock using a PIC 16C61.  In the tradition of Marv Newland's "BambI Meets Godzilla", there is far too much ROM space spent on credits, which are smooth-scrolled horizontally on the bottom of the screen. __ Designed by Eric Smith

PIC16F873 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 , PIC 16F873 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

PLD Implements Fast Four-Phase Clock Generator  -  10/27/94  EDN Design Ideas:  The circuit in Fig 1a can clock pipelined logic in PLDs by an external agent at one-half the usual frequency.  You can use this circuit when designing pipelined ALUs and switched-capacitor circuits.  I used this circuit to drive a 40M-sample/sec CMOS flash __ Circuit Design by Said Jackson, Hamburg, Germany

Poor Man's Timer  -  Often 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 Dave Johnson P.E.-August 24,2008

Procedure for DDR Clock SkeW & Jitter Measurements  -  Application Note # 028__ Pericom Semiconductor

Programmable Clock Oscillator  -  PIC -Tock video clock using a PIC 16C61__ Designed by Eric Smith

Programmable Divider Restores SVGA Pixel Clock  -  03/28/96 EDN Design Ideas:     if you've tried to design a video-overlay board that works with super-video-graphics-adapter (SVGA) graphics through a feature connector, you've probably noticed that the frequency of the supplied clock signal is not always equal to the pixel-clock frequency.  In high-color modes (32, 000, 64, 000, and 16 million colors) , the clock usually runs at 2 or 3x the pixel frequency. You can restore the pixel clock by using a simple programmable divider, as opposed to the more complex PLL circuit used in many video-overlay boards. Figure 1 shows the divider circuit __ Circuit Design by Piotr Mazur, Wikom, Warsaw, Poland

Projection Clock  -   I'm pretty nearsighted and also an intermittent sleeper, and it has always frustrated me to contort myself far enough to read my clock radio display without my glasses on. __ Designed by Markus Wandel

Prop Clock Project  -  A propeller clock is a fast rotating array of 7 high bright leds. After triggering the hall sensor it builds a virtual picture. The software is measuring the time of the rotations to justify the width. The power for the circuit board and the LEDs is inductive transferred by one of the video head coils. A infra red LED transfers the DCF signal to the pcb__ Designed by Lucifer Ursum

Propeller Message Display with Temperature Indicator  -  Here we describe a microcontroller-based propeller display that displays any message sent to it via hyper-terminal of a personal computer. Moreover, a temperature sensing IC (TMP125) is mounted onto the propeller display to display temperature in real time.  It gives a 360-degree view and displays several characters in a revolving circular path using just eight LEDs. The main highlight o this project is a vertical facing display with true 360-degree viewing angle. __ Designed by © EFY Enterprises Pvt. Ltd. All rights reserved.

Propellor clock PIC16F84  -  a few light emitting diodes spin, precisely controlled by a PIC  microprocessor, giving the illusion of a larger array__ Designed by Boblick

Provisionary Data Rates using the AD9951 DDS as an Agile Reference Clock for the ADN2812 Continuous-Rate CDR  -  AN-632 Analog Devices App Note__

Pushbutton Activates Service Request Beeper  -  A single press of a pushbutton switch turns on a beeper for one second but can’t be activated again for 60 seconds. . . . Circuit by David A. Johnson P.E.-July 09,2006

PWM fan controller in an EMI-susceptible circuit  -  02/16/06  EDN Design Ideas:     Control it with either an external negative-temperature-coefficient thermistor or a PIC  microcontroller and its SMBus serial-data bus __ Circuit Design by Dimitri Danyuk, Niles Audio Corp

PWM Motor Controller uses a 555 Timer  -  Using a CMOS version of the 555 timer, this circuit can be used to control the speed of a motor by adjusting the duty cycle of the pulses sent to the motor . . . Hobby Circuit designed by David Johnson P.E.-June 30,2006


Clock Circuits:   A - B      C - D      E - P      Q - Z


HOME Schematics Index Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches


 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |    Privacy Policy


Copyright  January, 1998 - December, 2017     David A. Johnson & Associates.  All Rights reserved. 


 Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.