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

 

Last Updated: October 18, 2017 05:04 AM

Circuits Designed by  Dave Johnson, P.E.

Quartz_Clock_Solar_Powered  -  Connect a solar panel to a quality AA size 1One of my homes in Colorado had a large battery powered quartz clock above the fireplace.  It was powered by an AA size 1.5v alkaline cell.  The battery would run the clock for about a year or so, then I would have to break out a tall step ladder and replace the battery for another year or so of operation. That gave me a great 10:1 energy margin. . . . Hobby Circuit by David Johnson P.E.-September 21, 2017

Service Request Beeper  -  A single press of a pushbutton switch turns on a beeper for one second but canít be activated again for 60 seconds. . . . Hobby Circuit designed by David A. Johnson P.E.-July 09, 2006

Solar Powered Quartz Clock  -  Connect a solar panel to a quality AA size 1One of my homes in Colorado had a large battery powered quartz clock above the fireplace.  It was powered by an AA size 1.5v alkaline cell.  The battery would run the clock for about a year or so, then I would have to break out a tall step ladder and replace the battery for another year or so of operation. That gave me a great 10:1 energy margin. . . . Circuit by David Johnson P.E.-September 21, 2017

Three-Minute Closet Light  -  I have a coat closet by my front door.  The thing is very dark at night and really needs some kind of illumination inside.  I could hire an electrician to install a light in the closet ceiling and then wire it to a toggle switch outside the door but that would cost me quite a bit of money . . . Circuit by Dave Johnson P.E.-December 25, 2011

Timer for Darkroom Camera Shutter  -  This circuit was designed to control a film exposure shutter for a darkroom.  It has 8 time steps ranging from 0.35 seconds to 4 seconds.  It is activated by a foot switch and draws power from an external 12-volt DC supply . . . Hobby Circuit designed by David Johnson P.E.-June 11, 2000

Watchdog Timer set for 36 Hrs  -  A watchdog timer is often used in computer systems to detect when a computer is hung up and is no longer running properly.  If it does become locked up and is not able to supply a reset pulse to the circuit within a defined time frame the timer times out a . . . Hobby Circuit designed by David Johnson P.E.-April 11, 2010


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

Quartz Clock Timebase  -  Many electronic projects call for a timebase generator, accurate to a second or so. One way of producing this is with a microcontroller, quartz crystal and some software. But a far cheaper and simpler approach is to recycle an old analogue quartz clock. must register on this site__ Designed by Published in Elecktor July/Augu, 2010

Quartz_Clock_Solar_Powered  -  Connect a solar panel to a quality AA size 1One of my homes in Colorado had a large battery powered quartz clock above the fireplace.  It was powered by an AA size 1.5v alkaline cell.  The battery would run the clock for about a year or so, then I would have to break out a tall step ladder and replace the battery for another year or so of operation. That gave me a great 10:1 energy margin. . . . Hobby Circuit by David Johnson P.E.-September 21,2017

Radio Clock for PC's  -  There are a number of low frequency time signals around the world that broadcast accurate time and date information. These signals are used by the many cheap radio controlled wall and desk clocks that can easily be purchased these days. The time signal is also useful for the synchronizing the clocks of computers__ Designed by Jonathan A. Buzzard

Railway clock WiFi ESP8266 - Lua  -  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

Realtime Clock With LCD Based On An Atmel AT89C4051  -  if you are looking for the simplest project, you are at the right place.  Its a digial clock which make use of AT89C4051 to work as a Real time clock. __ Designed by Ajay Bhargav ajay_bhargav @ hotmail.com

Real-time-clock chip makes low-power oscillator  -  11/23/00 EDN Design Ideas:  Many systems use watch-crystalbased, 32.768-kHz oscillators.  In battery-powered designs, the 32-kHz oscillator may consume a fairly high percentage of the total power budget.  Reduced power consumption.   PDF has many circuits, scoll to find this one __ Circuit Design by Yongping Xia, Teldata Inc, Los Angeles, CA

Relay clock  -  Even if relay logic is now an old technology, I havenít abandoned it. This  clock circuit  works for a sequence of 4 relays only, but the schematic is repetitive, so it may be extended. The relays K and K1 work in astable condition and are supposed to send the clock signal to the others. Once the circuit is supplied the cycle has to be triggered by pressing the button, then it continues without stopping__ Designed by Andrea-Central Italy

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__  by LTC Design Note

Scheme speeds access to ĶP's real-time clock  -  06/05/98 EDN Design Ideas:  (Scroll to find this circuit) The DS5000T (Dallas Semiconductors, www.  dalsemi.  com) is an 8051-compatible processor that integrates nonvolatile memory and a real-time clock.  This module has an impressive set of functional extensio __ Circuit Design by Jerzy Chrzaszcz, Warsaw University of Technology, Warsaw, Poland

Science of Timekeeping  -  Application Note__ Aligent

Service Request Beeper  -  A single press of a pushbutton switch turns on a beeper for one second but canít be activated again for 60 seconds. . . . Hobby Circuit designed by David A. Johnson P.E.-July 09,2006

Shift Register Divides Clock  -  01/05/95  EDN Design Ideas:  Check the circuit in Fig 1; it's more subtle than it first appears.  The 74HCT165 parallel-in, serial-out shift register digitally divideas an input clock by 2, 4, 8, or 16, depending on the bit pattern you load into the device.  Table 1 lists bit patterns f __ Circuit Design by C Shankar, ITI Ltd, Bangalore, India

Shot Clock 24 Second Timer  -  This is a circuit intended to be used in basketball shot clock. __ Designed by Milano de Guzman

Sidereal clock project withs  -  My first major digital electronics project, aged 14 I embarked on this digital clock project, sponsored by my Dad.  It took several years to complete, during which time it evolved into a sidereal clock. The inspiration for this project was an article in the July/August edition of Elektor Electronics, 1984. Every summer Elektor did this bumber edition containing over 100 small projects. I didn't buy Elektor regularly but every summer this bumper edition was a must.__ Designed by Hans Summers

Single Gate Synchronizes Clock  -  10/27/94 EDN Design Ideas:     The deceptively simple circuit in Fig 1 harbors formidable power.   Consider when you have a data-clock input to your system for an existing serial data stream.   Then, your system people surprise you __ Circuit Design by Phil Harvey, Technology Integration Inc/, Bedford, MA

Single-digit Nixie clock  -  A while ago I found a Burroughs B-5853 Nixie tube kicking around in the lab and decided that I should put it to good use. Since I only had one of this size, I wanted to make a single-digit display out of it. __ Designed by © 2007 Riad S. Wahby

Solar Powered Quartz Clock  -  Connect a solar panel to a quality AA size 1One of my homes in Colorado had a large battery powered quartz clock above the fireplace.  It was powered by an AA size 1.5v alkaline cell.  The battery would run the clock for about a year or so, then I would have to break out a tall step ladder and replace the battery for another year or so of operation. That gave me a great 10:1 energy margin. . . . Circuit by David Johnson P.E.-September 21,2017

Speed Acces to ĶP's Real-Time Clock  -  06/05/98 EDN Design Ideas:  (Scroll to find this circuit) The DS5000T (Dallas Semiconductors, www.  dalsemi.  com) is an 8051-compatible processor that integrates nonvolatile memory and a real-time clock.  This module has an impressive set of functional extensio __ Circuit Design by Jerzy Chrzaszcz, Warsaw University of Technology, Warsaw, Poland

SP-L Modulator uses Single Speed Bit Clock  -  08/15/97 EDN Design Ideas:     Split-level (SP-L) , or Manchester, encoding is a common modulation scheme in data transmission (Figure 1). SP-L is popular because bit-clock extraction at the receiving end is easy, and the modulator circuit is simple to implement--simple, but not trivial, because the output of this classic circuit suffers from severe spikes during data transitions (Figure 2). A different circuit eliminates the spiking problem (Figure 3). This circuit resamples data after stabilization, but to do so, it needs a double-speed clock. This need can be as annoying as having spikes.  __ Circuit Design by Massimo Garavaglia, Robecchetto con Induno, Italy

Sun-Up Alarm  -  The Sun-Up Alarm can be used to provide a audible alarm for when the sun comes up or it can be used in a dark area and detect when a light comes on.  It can also be used to detect a light beam, headlights etc. The circuit works as follows. The phototransistor is very sensitive to light. (Any phototransistor will work fine) __ Designed by Randy Linscott

Swiss Railroad Clock  -  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

System implements digital clock Modulation  -  10/28/04  EDN Design Ideas:  in spread-spectrum and direct-sequence receivers, it's often necessary to change the frequency of the clock oscillator, and thus the spreading-code clock, to lock the receiver's reference pseudorandom-noise code to the incoming cod __ Circuit Design by Dan Doberstein, DKD Instruments, Nipomo, CA

Tanktwanger puts a new spin on clock synthesis  -  02/03/97 EDN-Design Feature     An unusual circuit, the "tanktwanger, " provide as some clock-generating and -adjusting advantages over conventional clock-synthesis methods.  You can adapt the main circuit for numerous applications, but you must take care when constructing this VHF design.   __ Circuit Design by Glen Chenier, Fitel Photomatrix

Termination supply tracks one-half core voltage  -  04/27/00 EDN Design Ideas:     Modern ĶPs typically require core voltages of 2 to 3V.   They also require "termination" voltages that, for best performance, should equal half the core voltage.   The problem is, core voltages vary among CPUs, and some systems even incorporate variable-core-voltageModern ĶPs typically require core voltages of 2 to 3V.   They also require "termination" voltages that, for best performance, should equal half the core voltage __ Circuit Design by Chester Simpson, National Semiconductor, Santa Clara, CA

The Science of Timekeeping  -  Application Note__ Aligent

Three-Minute Closet Light  -  I have a coat closet by my front door.  The thing is very dark at night and really needs some kind of illumination inside.  I could hire an electrician to install a light in the closet ceiling and then wire it to a toggle switch outside the door but that would cost me quite a bit of money . . . Circuit by Dave Johnson P.E.-December 25,2011

Timer for Darkroom Camera Shutter  -  This circuit was designed to control a film exposure shutter for a darkroom.  It has 8 time steps ranging from 0.35 seconds to 4 seconds.  It is activated by a foot switch and draws power from an external 12-volt DC supply . . . Hobby Circuit designed by David Johnson P.E.-June 11,2000

Two nixie display clock  -  My clock building habit is apparently as bad as ever. This time, it was inspired by a stash of Burroughs B5092s, so I needed to vertically align it. Also, since I wanted to make it as small as possible, I wanted to keep nearly everything surface mount, so I abandoned the idea of using 74141s in favor of standard BCD to decimal converters plus some external drive transistors. No need to multiplex since  I'm only using two tubes, so this design is actually pretty straightforward. __ Designed by © 2007 Riad S. Wahby

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

Unusual clock with AT89C2051   -  interesting worked out example of clock with only 7 lad's   - published in magazine "Svijet elektronike" Nr.46 ( June / July 2004) Author: ivica Novakovic __ Designed by © Ivica Novakovic

Use a PC's parallel port to program a clock source  -  12/07/04  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 circui __ Circuit Design by William Grill, Honeywell BRGA, Lenexa, KS

Use a system's real-time clock to "hide" a code sequence  -  10/27/05  EDN Design Ideas:  Keep key code sections protected from prying users __ Circuit Design by Mihaela Costin, Delmhorst Instruments, Towaco, NJ

Using The AT89C4051 As A RTC (Real-Time Clock)  -  if you are looking for the simplest project, you are at the right place.  Its a digial clock which make use of AT89C4051 to work as a Real time clock. __ Designed by Ajay Bhargav ajay_bhargav @ hotmail.com

VCXO Makes Inexpensive Dual-Clock Reference  -  27-Nov-03 EDN Design Ideas:  This design idea describes an inexpensive circuit to generate two extremely high-quality, crystal-clock-reference-signals, one of which is a PWM-controlled VCXO (voltage-controlled crystal oscillator] clock signal (Figure 1).  The design also includes circuitry to statically switch and hold the VCXO at its nominal fixed frequency of operation (equivalent to 50% PWM] without requiring any externa __ Circuit Design by Said Jackson, Equator Technologies Inc, Campbell, CA

VFD (vacuum flourescent display) clock  -  This is my fifth retro display clock (others: 1, 2, 3, 4) , but the first based on a vacuum fluorescent display. Let's get right down to it. __ Designed by © 2007 Riad S. Wahby

Video Clock Superimposer using PIC16C711  -  As a followup to my VCR Pong project, here is a gadget that is actually useful in the Real World!  it superimposes the time of day, in "HH MM SS" format, in the bottom right-hand corner of an existing video signal. My friend Scott uses it with his home security system__

Wall Clock Governor Driver  -  These were common before the advent of quartz controlled stepping motor clocks. Here is a reverse engineered diagram of this very typical circuit. __ Reverse engineered schematic Stepan Novotill

Watchdog Timer set for 36 Hrs  -  A watchdog timer is often used in computer systems to detect when a computer is hung up and is no longer running properly.  If it does become locked up and is not able to supply a reset pulse to the circuit within a defined time frame the timer times out a . . . Hobby Circuit designed by David Johnson P.E.-April 11,2010

Weston Voltmeter Clock  -  This was the first clock I built, but I'vesince built a couple others, a single-digit NiXiE and a CRT clock, so the whole count-60-cycles seems like old hat at this point. The PIC  sits there interrupting on RA4/T0CKI and dutifully keeping count of those oh-so-accurate (at least, over long periods of time) cycles coming out of the wall.  __ Circuit Design © 2007 Riad S. Wahby


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

 


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