Timer Circuits

Fast charge Controller with MAX712 / MAX713

Fast charge Controller with MAX712 / MAX713

The MAX712 and MAX713 are nickel cadmium (Ni-Cd) battery fast charge controllers which will fast charge batteries from a DC source at least 1V higher than the maximum battery voltage. 1 to 16 series cells can be charged at rates up to 4C. A voltage-slope detecting analogue-to-digital converter, timer, and temperature window comparator determine charge completion. The MAX712 or 713 are powered by the DC source via an on-clip +5V shunt regulator, and draw a maximum of 5uA from the battery when not charging. A low-side current-sense resistor allows the battery charge current to be regulated while still supplying the power to the battery's load...

Water Softener Circuit

Water Softener Circuit

That circuit is based at a technique to remove or neutralize the salt in water, and protect the pipes at home as well as the washing machines or our selves from salt. Its called water softener and its automated circuit using two 555 timers. ..

18 LED sequencer timer

18 LED sequencer timer

The question sometimes comes up of how to cascade 4017 decade counters for more than 10 sequencial stages. The LED sequencer below shows a possible solution using a few extra parts. When power is applied, the 15K resistor and 10uF cap at pin 15 will reset the counters to the zero count where pin 3 is at +12 and all other outputs are at zero. The 2 diodes (1n914) and 15 resistor form a AND gate so the clock pulse will be passed to the right side counter when the sequence starts. When the right counter reaches the 10th count, pin 11 will move high enabling the AND gate on the right to pass the clock pulse to the left side counter. ..

Digital Clock with Solar Regulator

Digital Clock with Solar Regulator

The basic clock circuit (top schematic below) is similar to the binary clock (on another page) and uses 7 ICs to produce the 20 digital bits for 12 hour time, plus AM and PM. A standard watch crystal oscillator (32,768) is used as the time base and is divided down to 1/2 half second by the 4020 binary counter. One half of a 4013 data latch is used to divide the 1/2 second signal by 2 and produce a one second pulse that drives the seconds counter (74HC390 colored purple). The minutes are advanced by decoding 60 seconds (40 + 20) and then resetting the seconds counter to 0 and at the same time advancing the minutes counter. The same procedure is used to advance the hours. The second half of the 4013 latch is used to indicate AM or PM and is toggled by decoding 13 hours and resetting the hours to 0 and then advancing the hours to "one"...

Timer circuit II

Timer circuit II

Timers are fundamental building blocks, and as such timers are found in practically every electronic circuit. There are many kinds of timers, available off-the-shelf from resellers of electrical and electronics goods, because circuits circuits involving timers have thousands of practical applications. In this article we will explain how to build six different timers from the same base circuit. Nutchips are ideally suited for building timers. Not only the timers differ only for the truth table programmed inside the Nutchip, there is also room for ingenuity, and you master the basics you can customize the timer adding your custom logic to the truth tables shown here...

Timer circuit

Timer circuit

A wide rage auto turn OFF timer covering 1 minute to 20 hours in three ranges with S1. As soon as power is applied to the circuit the IC1 [555] starts to oscillate happily and feeds clock pulses to the IC2 [4017]. The IC2 [4017] and IC3 [4020] give a combined count rate of 81920 before the output of the IC3 [4020] goes high and turns Q1 on. With pot RV1 adjust the Time. ..

Timer Circuit with optocoupler

Timer Circuit with optocoupler

A small circuit that can find a lot applications of measurement time. She has the possibility us inform with sound signal from the BZ1. At the same time, exist the possibility drive a external circuit via the optocoupler IC2, after we connect the applicable circuit in contacts [ A ] and [ B ]. The circuit is based on IC1 (4060), which include in his inside, oscillator and a binary divider of 14 stage. The frequency operation of oscillator is determined by a circuit R-C that connected in pins 9,10,11 of IC1. We give supply in the circuit, with switch S1, is presented a pulse in 12 [ RESET ] via C1 and R3, null him counter, require the measurement of pulses to begin from the zero. ..

Timer switch circuit

Timer switch circuit

A 100 second delayed turn ON relay RL1 switch, if plug power +12V in circuit. In Fig.2 see a two range 6-60 second and 1-10 minute auto turn off relay timer circuit, with 555...

Timer and Interrupt

Timer and Interrupt

There are 4 timers in PIC18 which are timer0 to timer3. Timers are used when precise timing event need to be generated. Timers are usually used in conjunction with interrupt to keep the timing accurate. This guide will show an example of using timer0 to count a timer for every second. The circuit used for this example is the same as the circuit used in the PWM guide. The back light of the LCD will blink on and off every second, while the counter on the LCD will increase until it reaches 199 then reset back to 0. The counting of second is implemented using an interrupt service routine. The guide will be divided in to 2 parts, 1st part dealing with the setting on Timer0 and the second on the interrupt service routine...

Count Down Timer with PIC16F84A

Count Down Timer with PIC16F84A

The choice of material to read or drive is the definition of three digits (Bit), RA0, 1,2 PORTA of the PIC at the entrance of 74HC138A. To select a material for reading or driving an output of 78HC138 is '0 '(Low), forcing the transistor (2SA1015) to conduct and thus is the material with the feet of PORTB. This function ensures that there will never be found simultaneously connected to PORTB two materials, since the remaining transistors are off. Switches BCD (inputs), the start button (input) and LED Display (outputs) are controlled solely by the pins RB0 - RB7 of PORTB. Depending on what material is selected and modified the state of PORTB (If it is input or output). ..

68HC11 as a Digital Timer

68HC11 as a Digital Timer

The timer is proposed an effective model for controlling an external load 8A/380V. Equipped with a 68HC11 mu.P associated with an 8 MHz crystal, it can get very precise programmable durations. Two lines are planned: from 0 to 99 seconds and from 0 to 99 minutes. Both displays allow programming in conjunction with a 4-button keypad. They also display the count of elapsed time. The relay output double contact work controls the external load...

Greenhouse irrigation controller ( PIC16F84 )

Greenhouse irrigation controller ( PIC16F84 )

This is a simple one-valve irrigation controller made for our greenhouse. The code contains a software real-time clock (RTC) and a multiplexed 8-digit LED display and keyboard you can use in other projects. The operating software is simple, it contains a real-time clock and a day counter. The valve is turned on in regular intervals in the same time. Day setting specifies the number of days between the activations, time setting specifies the time of the day when to start. Duration is the time after which the valve will be turned off. MODE button cycles through clock, start time and duration settings. the interval and starting time set will be stored in the DATA EEPROM. Scheduling can be totally turned OFF by the ENABLE button. Irrigation can be manually turned ON/OFF any time by the START/STOP buttons ..

Light timer switch with PIC12F629

Light timer switch with PIC12F629

This is a lamp timer capable of operating two separate relay switches. Outputs can be in three (or restricted to two) states: OFF, delayed ON and constant ON. Delayed ON mode is indicated by the LEDs. The source code is easily customizable for your needs: set your desired delay time or disable constant ON state. press the button once to turn on the lamp for a pre-defined delay. while ON, press the button again to turn the lamp constant ON (turn off delay timer). press the button again to turn the lamp OFF. alternative operation, if you disable the constant ON mode: press the button once to turn on the lamp for a pre-defined delay. while ON, press the button again to turn the lamp OFF...

Count Down Timer Relay with 555

Count Down Timer Relay with 555

The 555 is configured in the standard astable oscillator circuit designed to give a square wave cycle at a period of around 1 cycle/sec. A potentiometer is included in the design so the period can be set to exactly 1 second by timing the LED flashesc. A jumper connection is provided so the LED can be turned off. As soon as power is applied to the circuit counting begins. We have not reviewed the operation of the 555 IC here. Most electronic magazines review it in detail once every few years. And it is a standard feature in most intoductory electronic text books. ..

Garden timer circuit with CD4000

Garden timer circuit with CD4000

The resulting timer circuit is made from a CD4060, includes an oscillator and a 14 stage binary counter, two CD4040's, which are 12 stage binary counters, a CD4012 Dual Nand gate and a CD4013 Dual D Latch. The CD4060 is connected to a 32768 Hz ECS 3X8 tuning form crystal. The 10 Meg Ohm resistor between CD4060 pins 10 and 11 are to bias the internal inverter into its analog region, and the 330 K resistor in series with the crystal is to limit the power to the crystal. This setup is directly from the ECS data sheet. The output of the 14th flip flop in the CD4060 appears on pin 3, and it is a 2 Hz square wave. A 2N4401 buffer drives a green LED with this square wave. When I see it blinking through the plastic window of the Irrigation System Controller housing, I know that power is on, and that at least the oscillator and first 14 counter stages are working. ..