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Timers and Counters Circuits

Timers & Counters:  #'s - A      B - D      E - L      M - S      T - Z


Last Updated: October 24, 2017 02:55 PM

Circuits Designed by Dave Johnson, P.E. :

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, 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, 2000

Two Transistor Oscillators -  This page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current. . . Circuit by David A. Johnson P.E.-December, 2002

Two-Transistor Low Power Oscillators -  This page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2002

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, 2010

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-368-7747

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

Ultra High Accuracy Digital Clock -  On these pages, the production of the digital clock that operates with very high accuracy by synchronizing to the color burst signal in the television picture signal is being mentioned.   __ Designed by Seiichi Inoue

Ultra High Accuracy Digital Clock (Ver2) -  On this page, I will introduce the digital clock with very high accuracy which controlled by PIC .  To be controlling in PIC  is only the feature of the clock.  The PLL oscillator to have made synchronize with the precision oscillator of the TV station is used to improve the precision of the clock.   __ Designed by Seiichi Inoue

Ultralow-cost, two-digit counter features few components -  17-Aug-06 EDN Design Ideas:  Two seven-segment displays and one microprocessor count from zero to 99 EDN-Design ideas __ Circuit Design by Noureddine Benabadji, University of Sciences and Technology, Oran, Algeria

Ultrapure 1kHz Sine Wave Generator -  A lamp provides amplitude stability while the very low noise amplifier creates a pure sine wave signal.  The R an C values set the oscillator frequency and the feedback resistor sets the lamp current and output amplitude.  __ Linear Technology/Analog Devices App Note, Jun 21, 2011

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

Uneven Clicks -  This circuit produces two clicks then a short space before two more clicks etc.  Changing the voltage on pin, 5 via the diode, adjusts the timing of the chip.  __ 555-Timer

Unidirectional counters accumulate bidirectional pulses -  04/11/02 EDN Design Ideas:  Quadrature-output incremental optical shaft encoders are popular in high-performance, bidirectional rotation-sensing applications.  Available with resolution options extending beyond 2000 pulses/revolution, incremental encoders provide a fast, inexpensive, and reliable way to digitally read out bidirectional mechanical motion __ Circuit Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC

Universal Counter -  Typical frequency counter that built by electronics hobbyists.  This counter can measure time periods and has communication interface, so that I named this "Universal Counter".   __ Designed by The Electronic Lives Manufacturing-presented Chan

Universal Timer with Zero Standby Current -  This design came about when the author wanted better control of his 12 V solar-charged garden lighting installation.  it is however a versatile circuit which can also be used to switch other types of equipmentmust register on this site __ Designed by Published in Elecktor July/Aug, 2010

Universal Watchdog Fully Controls µ Preset -  05/25/95 EDN Design Ideas:  Many µPs contain internal watchdog timers, and you may wonder why you need another stand-alone circuit.  Unfortunately, more highly integrated functions have preset parameters that you may want to change.  Also, internal watchdogs are generally a simple combination of a flip-flop and a timer.  if the program does not start properly on the first try, the timer is of no use because the program never turns on the watchdog.  This watchdog catches exactly this condition __ Circuit Design by Terje Kvinge, Nera AS, Kokstad, Norway

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

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

Up/Down Fading LED -  These two circuits make a LED fade on and off.  The first circuit charges a 100u and the transistor amplifies the current entering the 100u and delivers 100 times this value to the LED.  __ 555-Timer

USB Clock with LCD Readout, Pt.1 -  This LCD USB Clock connects to your PC's USB port.  it synchronises its time with your PC - and ultimately an internet time server - when your PC is on to maintain accurate time-keeping.  it can also operate on its own using battery back-up and has user-selectable display modes.__ SiliconChip

USB Clock with LCD Readout, Pt.2 -  Last month, we detailed the circuit of the USB Clock and showed you how to build it.  This month, we detail the software installation and describe how it is used.  We also describe how to synchronise your PC to an internet time server and how to synchronise the USB Clock to the PC each time the PC boots up.__ SiliconChip

Use a 555 timer as a switch-mode power supply -  14-Nov-02 EDN Design Ideas:  Most switch-mode power supplies rely on a PWM (pulse-width-modulated] output that is controlled via voltage feedback.  A 555-timer IC can inexpensively perform PWM.  The circuit in Figure 1 shows how to turn a 555 PWM circuit into an switch-mode power supply with only one simple equation.  The design uses two 555s __ Circuit Design by Aaron Lager, Masterwork Electronics, Rohnert Park, CA

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 PWM fan controller in an EMI-susceptible -  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

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

Use a trick to count scope events -  01/21/99 EDN Design Ideas:  One advantage digital storage oscilloscopes (DSOs] have over analog scopes is trace persistence.  You can easily see infrequent waveform features using a scope in infinite-persistence mode.  However, the frequency of these features relative to that of a "normal" signal   Page includes several designs.  Scroll to find this one __ Circuit Design by Allen Montijo, Hewlett-Packard, Colorado Springs, CO

Use Eight Timers with PIC16Fxxx Microcontrollers -  18-Feb-10 EDN Design Ideas:  Timers debounce switches and let you decide when lapses have expired __ Circuit Design by Luis G Uribe C, Caracas, Venezuela

Use Thermostat as 12 Volt Timer -  Find out how an old battery powered thermostat can be used as a low voltage automatic timer.   __ Designed by REUK-Renewable Energy UK website

Use time-domain analysis of Zobel network -  06/27/02 EDN Design Ideas:  A Zobel network is useful in making a reactive load appear as a pure resistance to a driving source prone to stability problems (Reference 1].  A typical situation is an audio power amplifier driving a loudspeaker, modeled at first approximation as an inductance and a series resistor (Figure 1a].  The addition of a series R2C network in parallel with the series R1L network forms a Zobel network __ Circuit Design by Noël Boutin, Université de Sherbrooke, PQ, Canada

Using 555 Timer as an A/D Converter -  Measure voltages accurately with a microcontroller using this simple circuit.  includes sample program for the Parallax Basic Stamp.   __ Designed by Boblick

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

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Timers & Counters:  #'s - A      B - D      E - L      M - S      T - Z


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