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Counters and Timer Circuits

2 Transistor Atomic Frequency Standard:

2.8 GHz Prescaler keeps Cost Down: 07/20/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find the one of interest /

28 LED Clock Timer 72 LED Clock: programmable clock Timer circuit that uses individual LEDs to indicate hours and minutes

4 Bit Binary Clock:

40 LED Bicycle Light (555 Timer 6 Volt):

5 to 30 Minute Timer:

50 MHz Frequency Counter, Voltage Meter & SWR / PWR Indicator:

555 Go / No Go Tester:

555 Makes handy Voltagetotime Converter: 02/01/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

555 One Shot: Basic 555 MonoStable Multivibrator

555 oscillator:

555 time Delay Circuit:

555 Timer #1:

555 Timer #2:

555 Timer 40khz Infrared Oscillator:

555 Timer Circuits:

555 Timer IC Tester:

555 Timer MonoStable Circuit using Pushbutton:

555 Timer Tutorial + Circuits:

555 Tone Generator 8 Ohm Speaker:

7 Segment LED Counter:

72 LED Clock:

8254 Timer & Counter Board:

9 Second Digital Readout Timer:

9 Second LED Relay Timer:

AD9852 DDS Schematic:

Amplifiers perform precision divide by 2 circuit: 03/06/03  EDN-Design Ideas / The classic implementation of a voltage-halving circuit uses two equal-value resistors. Using 1% resistors provides a divider output with 2% accuracy. For most applications, this performance is cost-effective and more than adequate. However, when you need extreme precision, this approach requires correspondingly accurate resistors and can become expensive...

Analog Pulse Counter:

Anticipating timer switches before you push the button: 04/03/03  EDN-Design Ideas / (Editor's note: This Twilight Zone-worthy circuit will be the subject of an upcoming network sitcom, My Big Fat Anticipating Timer.) It happens to almost everyone that an apparatus or system should have been turned off a moment ago. The device in question could be the car heater, the air conditioner, the lights

Asynchronous Circuit Divides Frequency By 1.5: 10/10/96 EDN-Design Ideas

Audio Amp Timer: Turns-off your amplifier when idle for15 minutes Fed by amplifier tape-output

Backup Clock Controller Checks Time Setting: 01/05/95 EDN-Design Ideas

Basic 555 Monostable:

BCD COUNTER: This is based around two ic’s the 4029 an up down counter and the 4543 a latched bcd to 7 segment driver it is very cheap to build with many uses.

Bedside Lamp timer:

Big LED Clock:

Binary Counter uses LSB Feedforward: 08/05/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Budget timer:

Car Clock: CaClo was designed and built to be used in an automobile. It uses pure discrete logic ICs (4000 series) and a4-digit LCD display with backlight, plus a few SMD ICs for the LCD driver.

Car Interval Wiper: CaWip was designed and built to be used in an automobile. Both the front and rear wipers can be controlled separately using six interval settings. Its a fairly old design, thats why theres no PIC microcontroller in sight! 

Cheap 40KHz Clock:

Circuit Conditions Variable Duty Cycle Clock: 01/05/95 EDN-Design Ideas

Circuit Converts Solid State Relay to Timer: 05/09/96 EDN-Design Ideas

Circuit Counts Logic ones on Signal Lines: 02/01/96 EDN-Design Ideas

Circuit divides frequency by N+1: 07/11/2002  EDN - Design Ideas / Digital frequency dividers usually use flip-flop stages that connect the Q pin to the D data-input pin of the following stage. This configuration creates a binary waveform that you can feed back to the input. You can divide any integer lower than 2N with minimal stages, where N is the number of stages..

Circuit provides linear resistance to time conversion : 08/07/03  EDN-Design Ideas / Resistance-based transducers, such as strain gauges and piezoresistive devices, find common use in the measurement of several physical parameters. For applications in which digital processors or microcontrollers serve for data acquisition and signal processing, the transducer's response must assume a form suitable for conversion to digital format....

Circuit Provides Serial or Sequential Timing: 09/26/96 EDN-Design Ideas

Circuit provides watchdog for microcontrollers: 12/26/2002  EDN - Design Ideas / The watchdog circuit in Figure 1 uses a single NAND Schmitt-trigger IC. The circuit is more cost-effective than dedicated, commercially available watchdog ICs. The circuit generates an active-high reset signal upon power-up and remains in a low state as long as the control input receives pulses. Whenever the pulsing at the control input stops, whether the circuit is in a high or a low state, th....

Clock Divider Circuit:

Clock Doubler for CMOS Logic:

Clock Fail Circuit Switches to Alternate Clock: 10/24/96 EDN-Design Ideas

Clock Generator: Use4093 oscillator

Clock Recovery PLL Fits Into Single PLD: 11/23/95 EDN-Design Ideas

Clock Switching Circuit Banishes Glitches: 12/19/96 EDN-Design Ideas

CMOS 4011 oscillator:

Computerised Universal Timer:

Countdown timer With Relay:

Counte Resets LRS Generator : 09/30/02 Electronic Design - Ideas for Design / A linear-recursive-sequence (LRS) generator produces binary sequences using a shift register and feedback through an exclusive-OR gate. The sequence length equals 2N­1, where N represents the number of registers. The generator cycles...  

Counter IC Provides Wait States for 8031 / 8051: 06/22/95 EDN-Design Ideas

Counter Provides Divide By 4.5 Function: 05/22/97 EDN-Design Ideas

Counter Speed Doubler:

Crystal Controlled Time Base Generator: Crystal Controlled Time-Base Generator

CW Beacon Keyer:

Darkroom Timer:

Day / Night / 24 Hour Select Sensor:

DDS using AD9835:

Delay line has wide duty cycle range: 06/27/2002  EDN - Design Ideas / Today's digital delay lines can process pulses no shorter than their delay times, and that restriction confines the devices to applications in which the duty cycle remains near 50%. A limited range of available delays (2 to 100 nsec per tap) further limits their use. Longer delay is available with one-shot multivibrators of standard digital-logic families, but those devices do not retain duty-c....

Delay Line implements Clock Doubler: 07/18/96 EDN-Design Ideas

Deoderizer Fan Pushbutton Timer :

Design low duty cycle timer circuits: 08/22/2002  EDN - Design Ideas / Designing astable circuits using the industry-standard 555 timer is a straightforward process when duty cycles are 50% or greater. However, you must overcome the many pitfalls of low-duty-cycle circuits to arrive at a desired result. Using only ideal components eases the design, but the components themselves are hard to obtain..

Digital Step Km Counter Max.: Pedometer has a range of 9.950 meters with2-digits. Slip it in pants pocket for walking and jogging

Digital Timer has Independent On / Off Periods: 03/28/96 EDN-Design Ideas

Divide By 1 1/2 Circuit:

Doorbell With Counter:

Dynamic Clock Provides for Zero Wait States: 03/27/97 EDN-Design Ideas

Edge Detector Runs off of Single Supply: 12/04/97 EDN-Design Ideas

Event Counter:

Extend the timing capabilities of a PC: 01/10/2002  EDN - Design Ideas Even when you use the internal timing registers and under DOS, a PC cannot easily measure time intervals with better time resolution than a millisecond. Measuring long intervals with even this precision is a waste of many CPU cycles. A microcontroller is well-suited for this task; you can easily integrate a PIC with a PC to extend the timing precision into the microsecond range for perio...

Failed Power Light: turns on small low voltage lighting when mains power disappears

Fast Rise time Multivibrator:

Frequency Counter:

Frequency Generator, 555IC:

Function Timing Analyzer: The idea behind FuTA was to measure the execution Time, of several selected functions (written in C), of a 6833232-bit microprocessor embedded system. Although this could be achieved by other means, such as an emulator (or simulator), it gave me an excuse to design some hardware using a PLD (programmable logic device). 

Galloping Neon: array of blinking neon lamps

Generating a Delayed Pulse With a Dual 555 Timer:

Generation Of 1 Sec. Pulses Spaced 5 Sec. Apart:

GPS Receiver Based Frequency Standard:

Impulse Counter: ImCo was really designed for a "bike-o-meter" project, but could used for all sorts of counting applications. It consists of a4-digit LCD display and several CMOS4000 ICs, running on a small 6V camera battery. It was built using SMD components (apart from the LCD and switches) in order to keep the size fairly small.

Jogging timer: 3V Battery Powered Beeps after a fixed number of minutes

Lamp Switch Delay:

LM3900 Sine Wave oscillator:

Logic offers complementary switch control: 12/06/2001 EDN - Design Ideas / The complementary-switch controller in Figure 1 uses a few inverter gates to provide drive signals for the complementary switches. Complementary-switch configurations find widespread use in synchronous-rectification circuits, charge pumps, full-bridge control circuits, and other circuits. The circuit in Figure 1 provides not only a complementary drive signal but also a deadtime delay ... .

Long Period timer:

Low Frequency Clock:

Mains Clock Controller using AT89C2051:

Micropower Pulse Generator:

MM58174Real Time Clock in a Battery Backed Up: Design Provides Reliable Clock and Calendar Functions :  National Semiconductor Application Notes,04-Nov-1995

More Accurate PC / AT Clock: Nixie Tube Clock

NAND Gates Enable Trigger Lockout For 555 Timers: 04/14/03 Electronic Design - Ideas for Design /  Applications of commercially available integrated timers, including the NE/SE555, are fairly limited when used in their monostable mode. This is due to their inability to function with all types of trigger pulses. These timers work perfectly and...

NE555 Basic Monostable:

Nixie Tube Clock:

Off the Shelf Watchdog: 01/07/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Old Dog 555 Learns Six New Tricks: 05/11/95 EDN-Design Ideas

Onboard Fogger Timer:

One Transistor timer:


Periodic Timer:

PIC Tock Video Clock:

Power On Time Delay Relay Circuit:

Precision 1Hz Clock Generator using Chip On Board:

Programmable Clock Oscillator #1: voltage controller oscillator that was designed as a wide range oscillator to generate clock pulses for a stepper motor drive system, frequency could be varied over1,000,000:1

Programmable Clock Oscillator #2: PIC-Tock video clock using a PIC16C61

Propeller Clock: a few light emitting diodes spin, precisely controlled by a PIC microprocessor, giving the illusion of a larger array.

Pulse Generator, 555:

PWM Watchdog Circuit Ensures upper Bounds: 11/07/96 EDN-Design Ideas

Realtimeclock Chip Makes Lowpower oscillator: 11/23/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Sample hold Controlled oscillator:

Shower Stopper:

Simple Circuit Provides Timebase Calibration: 04/24/97 EDN-Design Ideas

Simple Divide by N Using '161s:

Simple Frequency Doubler:

Simple FSK Modulator:

Simple phototimer controls load: 04/18/2002  EDN - Design Ideas / In industrial and home applications, the need sometimes exists for a device that, after activation by some physical effect, such as light, temperature, or sound, switches a load on for a predetermined time. The load, such as a lamp, motor, solenoid, or heater, usually derives its power from the ac line. .

Simple Timer Exploits OpAmp Bias Current: 07/21/94 EDN-Design Ideas

Simple Timer Remembers your Rhythm: 01/05/95 EDN-Design Ideas

Sine Wave oscillator:

Sinewave Frequency Doubler:

Single Gate Synchronizes Clock: 10/27/94 EDN-Design Ideas

Sleep Switch Cum Wake up Timer:

Slot Car T Volt Chronograph:

Speaking Clock using PIC & ISD Device: SpeClo was designed and built to be used by the blind. Its purpose is to provide a relatively easy way for ascertaining the Time of day by whistling, and can be configured to speak English or German!

Square Wave to Sine Converter:

Stable 40KHz Clock:

Stable Multivibrator (IC):

Stable Multivibrator (Transistor):

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) The sun shining on this device will provide a high to one of the NAND gates. This will cause another NAND gate to oscillate which will drive another gate to output a100hz tone. The transistor provides drive for the speaker.

Switch Debounce using 555:

Tan Timer: Six Timing positions suited to different skin types Timing affected by sunlight intensity