Page 16 of Clock Electronic Electronic Circuits

Clock Circuits
Clocks: #-A B-C D-G H-O P-S T-Z

Last Updated on: Wednesday, June 02, 2021 04:22 AM

Circuits Designed by Dave Johnson, P.E. :

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., 04/11/10]

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

Unusual clock with AT89C2051 - . . . [English version link]

Use a PC's parallel port to program a clock source - 12/07/04 EDN Design Idea 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. . . [by William Grill, Honeywell BRGA, Lenexa, KS]

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

Use a system's real-time clock to hide a code sequence - 10/27/05 EDN Design Idea Keep key code sections protected from prying users. . . [by Mihaela Costin, Delmhorst Instruments, Towaco, NJ]

Use Eight Timers With PIC16Fxxx Microcontrollers - 02/18/10 EDN Design Idea Timers debounce switches and let you decide when lapses have expired. . . [by Luis G Uribe C, Caracas, Venezuela]

Using Timer 1 in Asynchronous Clock Mode - Application Note Published 22-Nov-99. . . [Microchip]

VCXO Makes Inexpensive Dual-Clock Reference - 11/27/03 EDN Design Idea 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 desi. . . [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. . . . [© 2007 by Riad S. Wah[by]

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 by 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., 04/11/10]

Weston Voltmeter Clock - This was the first clock I built, but I've since 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. . . . [© 2007 by Riad S. Wah[by]

Yet Another Clock Featuring the PIC16c924 - Application Note Published 26-Aug-97. . . [Microchip]

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Clocks: #-A B-C D-G H-O P-S T-Z