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

DiscoverCircuits.com has links to 45,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.

HOME Schematics Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches
Welcome to DiscoverCircuits.com - online since 2002

See Media Kit for
Advertising Opportunities

Attention Designers:  Please alert us by eMail if we have linked to sites
where your original material has been copied without your permission.
We will change to the LINK to your site.  
Thank you.

 


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. :
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.-September, 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.-May, 2012

On/Off Latch Circuit with 2 Second Delay -  A Discover Circuits visitor needed a latch circuit which could operate using a power supply voltage ranging from 3v to 24v.  He wanted to use a tiny pushbutton switch to turn on and off power to a load.  However, he wanted a 2 second delay between the switch activation and the state change of the output. . . Circuit by Dave Johnson P.E.-June, 2013

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, 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, 2008

Press & Hold Latching Circuit -  A Discover Circuits visitor needed a latch circuit which could operate using a power supply voltage ranging from 3v to 24v.  He wanted to use a tiny pushbutton switch to turn on and off power to a load.  However, he wanted a 2 second delay between the switch activation and the state change of the output . . . Hobby Circuit designed by David Johnson P.E.-June, 2013

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.-September, 2005

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.-February, 2007

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. . . . Hobby Circuit designed by David A. Johnson P.E.-September, 2005

Consulting Services include:
Applications Engineering   --    Design & Development
Electronic Circuit Design   --   Custom Test Fixtures

Call 806-368-7747


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

Quad Astable Mode Operation Free Running Oscillator -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

Quad Monostable Mode Operation One Shot Pulse -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

Quadrature Sine Wave Oscillator. Voltage Controlled Frequency Range from 2Hz to 18kHz with 1VP-P Constant Output Amplitude -  The LTC6990 is a precision silicon oscillator with a programmable frequency range of 488Hz to 2MHz.  it can be used as a fixed-frequency or voltage-controlled oscillator (VCO).  The LTC6990 is part of the TimerBlox family of versatile silicon timing devices.  A single resistor, RSET, programs the LTC6990’s internal master oscillator__ Linear Technology/Analog Devices App Note, Jun 16th 2010

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/Aug, 2010

Quartz Crystal Synchronizer for Pendulum Windup Wall Clock -  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

Quirky 555 Timer Reset Function -  How many have had legitimate problems with the 555 timer? Let me guess…it involved the reset line, did it not? We all know that pin 4 must be set high before oscillation begins, but what is its threshold? input current? and what happens when it is operated slightly out of spec? This may be the very first attempt in __ Designed by Jim Keith

Quiz -  This project can be used for a quiz with up to 4 contestants (or teams).  Each contestant has a trigger push-switch and LED.  When a trigger switch is pressed it lights the corresponding LED, sounds the bleeper and prevents the other trigger switches from working - therefore showing which contestant was the first to press their switch __ Designed by John Hewes

Radio Clock for PC's -  The heart of the device is a EM2S receiver module and matching antenna.  The two are matched, so a mixing a 60kHz receiver board suitable for the MSF and WWVB signals with a 77.5kHz antenna and vice versa will not work.  it should be noted that the receiver boards know nothing about the format of time signal itself so a 60kHz pair suitable for receiving the MSF signal will also receive the WWVB signal __ 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

Rainbow Clock -  Here is a simple circuit using different colour LEDs that makes your clock glow in different colours of rainbow.  The clock’s dial (shown in Fig.2) is lit by colour LEDs...__ Electronics Projects for You

Random' Flasher for 8 LEDs -  This project uses a 4026 counter and display driver IC to flash eight LEDs in an apparently random manner.  it can be used to create a display of your choice.   __ Designed by John Hewes

Ratiometric Sensor to Pulse Width, Non-Inverting Response -  The LTC6992 is a silicon oscillator with an easy-to-use analog voltage-controlled pulse width modulation (PWM) capability.  The LTC6992 is part of the TimerBlox family of versatile silicon timing devices.  A single resistor, RSET, programs the LTC6992’s internal master oscillator frequency.  The output frequency is determined__ Linear Technology/Analog Devices App Note, Jun 16th 2010

RC Servo Tester with 555 IC -  Servo refers to an error sensing feedback control which is used to correct the performance of a system.  Servo motor is a DC motor equipped with a servo mechanism for precise control of angular position.  Servo motors usually have a rotation limit from 90° to 180°.  Servos are used for precision positioning in robotic __ Designed by T.K. Hareendran

RC-Timed Shutoff Function Uses Op Amp & Momentary Switch -  02/16/12  EDN Design Ideas:  Battery-operated instrument benefited from auto-power shutdown.  A handheld, battery-operated “fiber finder” measures the light escaping from an optical fiber when clamped in a V-shaped block under slight pressure.  A pair of photodiodes on each side of the resulting bend compares analog levels to indicate the presence and direction of light travel, and PLL tone decoders indicate the presence of as many as three optical-modulation tones.  The idea is to “tag” a fiber with a central-office signal __ Circuit Design by Glen Chenier, Teeter Totter Tree Stuff, Allen, TX

Reaction Time Game -  A clever design to test your knowledge about counters, state machines, displays, and how to put them together.  Not only this project is very suitable for the schools, it is also very fun! ! !  This reaction time meter measures your reaction time, and can be built on a breadboard.   __ Designed by Projects & Ideas from Nutchip.com

Reaction Timer -  The circuit below can be used to test a person’s reaction time to a precision of ±0·01 seconds.  The time is indicated by a series of seven LEDs showing the output of a binary counter (4060).  The two D type flip-flops are in a 4013.  The LED shown on the circuit diagram is the "stimulus".  Switch S1 starts the timer and illuminates the stimulus led.  Switch S2 stops the timer __ Designed by © David Hoult

Reaction Timer Game -  This is a game for two players.  Player 1 presses the START button.  This resets the 4026 counter chip and starts the 555 oscillator.  The 555 produces 10 pulses per second and these are counted by the 4026 chip and displayed on the 7-Segment display.  __ 555-Timer

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

Regularly Repeating Interval Timer -  Timer Circuits:  This circuit has an adjustable output timer that will re-trigger at regular intervals.  The output period can be anything from a fraction of a second to half-an-hour or more - and it can be made to recur at regular intervals of anything from seconds to days and beyond.  __ Designed by Ron J.

Relay clock -  Even if relay logic is now an old technology, I haven’t 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

Relay Delay -  This circuit waits for a set time and then activates a relay.  With the cap that is in the schematic you will get about a 6 sec delay till power on.  You can change the cap in this circuit to 470uF for about a 20 sec delay__ 

Relay Toggle Circuit Using a 555 Timer -  This 555 timer circuit below toggles a relay when a button is pressed.  Pins 2 and 6, the threshold and trigger inputs, are held at 1/2 the supply voltage by the two 10K resistors.  When the output is high, the capacitor charges through the 100K resistor, and discharges when the output is low.  When the button is pressed, the capacitor voltage is applied to pins 2 and 6 which causes the output to change to the opposite state __ Designed by Bill Bowden

Relay Toggle Circuit Using a 556 Timer -  This toggle circuit operates by using a couple 555 timers wired as inverters.  Pins 2 and 6 are the threshold and trigger inputs to the first timer and pin 5 is the output.  The output at pin 5 will always be the inverse of the input at pins 2 and 6.  Likewise, the output at pin 9 of the second timer will always be the inverse of the input at pins 8 and 12.  A 100K resistor connects the output of one inverter to the input of the other so the state of one will be the opposite of the other. __ Designed by Bill Bowden

Relay Toggle using a 555 Timer -  This is probably the best toggle circuit.   __ Designed by Bill Bowden

Relay: Delayed Turn-on -  This circuit is a delayed turn-on relay driver and can produce time delays for up to several minutes with reasonable accuracy.  The 14001 (or 4001) CMOS gate here is configured as a simple digital inverter.  its output is fed to the base of a regular 2N3906 (PNP) transistor, Q1, at the junction.   __ Designed by Tony van Roon  VA3AVR

Relay-12 Sec to 90 min -  Schematic and notes only, no circuit description provided.   __ Designed by Tony van Roon  VA3AVR

Reliable 555 Timer Doesn’t Falsely Trigger -  01/06/11 EDN Design Ideas:  Powering the timer from a NOR gate keeps it unpowered until needed.   [Design ideas by John Dawson, Opelika, AL __ Circuit Design by John Dawson, Opelika, AL

Remote Controlled Lighting -  This remote controlled switch circuit can control AC loads such as lights, fans etc through the remote handset of TV.  it uses the 555 timer in the bistable mode.  in the bistable mode output IC 555 keeps two states, either low or high.  When a negative pulse is applied to the trigger pin 2 of 555, the output turns high and __ Designed by D Mohankumar

Renewable Energy Powered Timer Relay Switch -  Powering an AA battery powered timer thermostat directly with a 12V power source.   __ Designed by REUK-Renewable Energy UK website

Repeat Timer -  Make a repeat timer circuit with large intervals between ON times.   __ Designed by REUK-Renewable Energy UK website

Repeating Interval Timer No.2 -  This circuit is based on a simple asymmetric oscillator.  The length of time the relay remains energized - and the length of time it remains de-energized - are set independently.  With the component values shown in the diagram - both periods are adjustable from about 1 to 30 minutes __ Designed by Ron J.

Repeating Interval Timer No.2 -  Timer Circuits:  This is a simpler repeating timer circuit.  it uses just one CMOS IC - wired as an asymmetric oscillator.  The length of time the relay remains energized - and the length of time it remains de-energized - are set independently.  __ Designed by Ron J.

Repeating Timer No.3 -  Timer Circuits:  This circuit is very similar to Repeating interval Timer No.2 .  However - the addition of a light dependent resistor means that the operation of this timer can be limited to the daylight hours.  A variable resistor (preset) lets you choose the level of darkness at which the timer will cease to function.  __ Designed by Ron J.

Repeating Timer No.4 -  Timer Circuits:  This circuit is the opposite of Repeating Timer No.3 .  its operation can be limited to the hours of darkness.  Again - the variable resistor (preset) lets you choose the level of darkness at which the timer will begin to function.  __ Designed by Ron J.

Repeating Timer No.5 -  Timer Circuits:  This circuit is a temperature controlled version of Repeating Timer No.3 .  The light dependent resistor has been replaced by a temperature dependent resistor or thermistor.  And a small preset potentiometer lets you choose the temperature above which the timer will operate.  __ Designed by Ron J.

Repeating Timer No.6 -  Timer Circuits:  This circuit is the opposite of Repeating Timer No.5.  it will only begin to operate if the temperature falls below the preset level.  Again - the variable resistor (preset) lets you choose the temperature below which the timer will function.  __ Designed by Ron J.

Repeating Timer No.7 -  Timer Circuits:  This timer is based on a simple CMOS 4001 Monostable Circuit.  The length of the ON period - and the length of the OFF period - can be set independently.  With the right value timing components - periods of up to an hour or more are available.  __ Designed by Ron J.

Repeating Timer No.8 -  Timer Circuits:  This circuit has an adjustable output time of up to one-hour.  And it can be set to repeat at intervals of up to 24-hours and beyond.  it's a single IC version of my first - CMOS 4060 based - Repeating Timer.  __ Designed by Ron J.

Repeating Timer No.9 -  Timer Circuits:  This circuit has two independently adjustable 24-hour timers.  There's a relay-timer that will energize the relay for up to 24-hours.  And there's a repeat-timer that will restart the relay-timer - at regular intervals of up to 24-hours.  it's a more versatile version of my first Repeating Timer. __ Designed by Ron J.

Replacing 556 with two 555's -  Here is a handy reference to replace a 556 dual timer with two 555's__ 555-Timer

Reverse Bias Oscillator -  There are a number of npn transistors that will oscillate in the audio range when reverse biased. Minimum supply voltage is 7V for low power transistors such as BC109, BC238 and 2N2222A, it becomes 12V for medium power transistors such as BD139 and is 16V for power transistors as BUX22 and 2N6543. Current drain is 4mA at 9V and frequency of oscillation is 550Hz. The base is normally left open. __ Contact  G. Forrest Cook

Robust 10MHz reference clock input protection & distributor for RF systems -  07/31/14  LTC Design Notes: Design a protected 10MHz reference input without degrading phase noise. __ Circuit Design by LTC Design Note

Room Sentry -  counts the number of people entering a room, for use with a pir module __ Contact P. Townshend - EduTek Ltd

Rotation Counter -  Presented here is a simple rotation counter which helps you measure the revolutions per minute (rpm) of any rotating object.  As the project requires measurement of very high rpm, a fast-switching...__ Electronics Projects for You

Roulette -  This circuit creates a rotating LED that starts very fast when a finger touches the TOUCH WiRES.  When the finger is removed, the rotation slows down and finally stops.  __ 555-Timer

Routing: the Next Big Problem in Physical Design -  05/28/01  EDN Design Ideas:  San JoseRight about the time the country was counting and recounting votes in the presidential race, another counting and recounting was taking place: the number of tape-outs using new physical-synthesis tools.  The attention paid to this event is understa __ Circuit Design by Joe G. Xi

RPM Counter using Microcontroller AT89c4051 -  Counting the revolutions per minute (RPM) of motors—determining the motor speed— is essential in the field of industrial automation.  it is useful especially for closed-loop control systems where proper action can...__ Electronics Projects for You

Rules of Thumb Aid in Timeconstant Analysis -  11/07/97 EDN Design Ideas:  An RC circuit charges or discharges to within 36.8% of the total excursion in one time constant, t, where t=RC.  However, 36.8% is an awkward figure, and you usually need a calculator to achieve reasonable accuracy.  You need a sho __ Circuit Design by Tony Zizzo, Burr-Brown, Tucson, AZ

Got Designs?
Please eMail
if you want me to link to and/or post your original design.  Thanks.

      <<<         >>>


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

 


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


Discovercircuits.com endeavors to credit original designers.   Please alert us by eMail so we can
delete links to material that have been copied without your permission
.   Thank you.


© Copyright of all original material on this website is the property
of David A. Johnson, P.E. (Dave Johnson & Associates ) unless otherwise noted.  

Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.
All material is provided "as is" without guarantees or warranty of any kind, either expressed or implied.