Digital Clock Timer Circuit

Digital Clock with Alarm Using DS1307
DS1307 is a hardware realtime clock, which works on I2C protocol.
Better graphics using the same old fashioned alphanumeric LCD
(type HD44780). Icons which shows the status for Alarm ON/OFF
state, which gives a nice and cute look to the clock.


PIC Digital Clock Timer
This clock timer uses a PIC16F628 microcontroller to display 3
and 1/2 digit time and control an external load. The clock includes
a calendar with leap year and optional daylight savings adjustments.
The timer output can be set from 1 to 59 minutes and manually
switched on and off. The clock also has a correction feature that
allows an additional second to be added every so many hours to
compensate for a slightly slow running oscillator. The oscillator
uses a common 32.768 KHz watch crystal and the frequency can
be adjusted slightly with the 24pF capacitor on the right side of the
crystal.



PIC Digital Multiple Clock Timer
This circuit uses the PIC16F628 microcontroller to provide 4
timed outputs that can be programmed from 1 minute to 1 week.
An extra 8 bit shift register (74HC164) is used for the 4 timer
outputs and to display four additional indicator lights.



Digital Clock with Timer and Solar Panel Regulator
This is a combination digital clock timer and solar panel charge
controller used to maintain a deep cycle battery from a solar panel.
The timer output is used to control a 12 volt load for a 32 minute
time interval each day. Start time is set using 9 dip switches and
ends 32 minutes later. The 32 minute duration is set by selecting
the 5th bit (2^5 = 32) of a 4040 binary counter (pin 2). The timer
also has a manual toggle switch so the load can be manually
switched on or off and automatically shuts off after 32 minutes.
The time duration can be longer or shorter (8,16,32,64,128,256
minutes etc.) by selecting the appropriate bit of the counter.
The timer circuit is shown in the lower schematic just above the
regulator.

Digital Clock with MM5314N
The digital clock of circuit, has as base one IC, the MM5314N,

in which are contained all the circuits that need. The IC1

collaborates with six Display of common anode, that are not

critically as materials. You can select what dimension, you want

it is enough you adapt pins their in the circuit. The display are

drive by a system of polyplexis and are drive by thirteen

transistors. For timing the circuit, is used the frequency of

network (50HZ). This solution is the simplest, that it is not best.

For more constant frequency you can use a circuit that would

be based on crystal,

7-Segment Digital clock circuit

Build a digital clock that turns AC load on/off with preset time

Figure 1 shows a circuit diagram of the Clock Controller V1.1.
P10-P1.7 drives 7-segment common anode LED with sink current.
P3.0-P3.3 also drives a base pin of 4-PNP transistor, 2n2907 with
sink current. As shown in the figure, the 2nd 2-digit LED that
connected to P3.2 and P3.3 is rotated 180 degrees to the 1st
2-digit allowing the pt. segment to be used for 1 second blinking.
P3.0-P3.3 also connects four momentary switches while the other
legs are tied to input port P3.4. During display and key switch
scanning, a logic '0' is shifted from P3.0 to P3.3, if there was a
key pressed, P3.4 then became low. P3.7 is a 1-bit sink current
driving, an example in the circuit uses a 2n2907 to drive a small
electromechanical relay 5V, say.

Blue Clock (Atmel Atmega8535 microcontroller)
The power comes in at the top left of the schematic. A bridge
rectifier is used so the polarity of the input signal doesn't matter.
A small SOT223 package, 5V regulator is used to provide
regulated voltage the Atmega8535, RTC, and the LED display
drivers. The Real Time Clock data is comes in from the PCF8563P.
This IC has a 32.768 crystal to keep time and a uses a 3V
CR2032 lithium battery when powered down. SW1 - SW4 are
the four pushbuttons for user input. The MBI5027 constant current
display drivers (24 pin DIP) from Macroblock can be a little hard
to find. They use power directly from the wall transform to turn
on the 7 segment LED's.




AVR 7-segment clock
The circuit can be viewed in every electronic book. Some
7-segments and LED's arranged as a matrix in rows and
colums and a multiplex routine written in assembler. The two
buttons are for setting the time.



Realtime clock with LED display and 89S8252
A real time clock using six 7-segment displays is used in this
project to display the time in HH-MM-SS format using a micro
controller ATMEL-89s8252 with minimum number of external
components. Five switches are used to set the HOURS
MINUTES (+/-) and one for zero reset of the clock display.
The micro controller runs of a 6Mhz crystal which also acts as
the time base for the clock.


Digital Clock with PIC16F84A
This is a small ajustable clock, I made based on PIC16F84A
microchip.The hardware part is very simple because it only
uses 74hct238 demultiplexer, 4x7 segments, and some rezistors.
The software part is programmed through a device connected to
serial port with icprog and made/debuged with MPlab.

Timer Circuit

Asymmetric Timer
A simple astable timer made with the 555, the mark (on)
and space (off) values may be set independently. The timing
chain consists of resistors Ra, Rb and capacitor Ct. The
capacitor, Ct charges via Ra which is in series with the
1N4148 diode. The discharge path is via Rb into into pin
7 of the IC. Both halves of the timing period can now be set
independently.


Timer Circuit
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.

Timer circuit
The erasing time of an EPROM variate about 10 to 40 minutes.
It is a pity to waste our time to waiting it while watch the clock
round until the EPROM has to be erased. Here a circuit to get
the perfect time while it is erased, we can do some another
work and let the eraser work by it self. Figure I-2. shows
this timer circuit diagram.

ames timer
Although the diagram looks complicated, you should be able
to identify the important sections of the circuit. Look first for
the 2-pole 6-way rotary switch. Pole A is used to select the
appropriate value for RT . Only one of the timing resistors can
be in the circuit. For example, if the switch is operated so
that the 18 kW resistor is selected, the timed interval will be 1
minute.

CMOS 24.055 Hour Timer
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.

Electronics timer by CD4060

This is an electronics timer by CMOS CD4060 which is CMOS
14 Stage Ripple-Carry Binary Counter/Divider and Oscillator.

Two 24-Hour Timer Circuits
These two circuits are multi-range timers offering periods of
up to 24 hours and beyond. They can be used as repeating
timers - or as single-shot timers. Both circuits are essentially
the same. The main difference between them is their behaviour
in single-shot mode.

In single-shot mode - when the preset time has elapsed - Version
1 energizes the relay and Version 2 de-energizes the relay. The
first uses less power while the timer is running - and the
second uses less power after the timer has stopped. Pick the
one that best suits your application.

Repeating Timer
The Cmos 4060 IC has two built-in inverters - at pins 9, 10 and
11. They must be wired together to form an oscillator - the
output of which is at Pin 9.
While the oscillator is running - Pin 9 is switching continuously
from high to low and vice-versa.

Analog Time Delay Circuit

Time Delay Circuits
Short timing functions such as a pulsed outputs or time delays
can also be created with one or two comparator sections.




Low Voltage, High Current Time Delay Circuit
In this circuit a LM339 quad voltage comparator is used to
generate a time delay and control a high current output at low
voltage. Approximatey 5 amps of current can be obtained
using a couple fresh alkaline D batteries. Three of the
comparators are wired in parallel to drive a medium power
PNP transistor (2N2905 or similar) which in turn drives a high
current NPN transistor (TIP35 or similar).

Turn on delay circuit
As you can see there is a RC timing network. Timing resistor is
variable type. Also there is a fast discharge network R2+Q1,
which provides fast discharge of capacitor when input signal
drops and fast turn off the relay . Q1-BD140 , D6-1N5819 or
similar, R2 -510R.

Turn off delay circuit
This circuit differs from upper circuit by momentary charging
timing capacitor. When input signal drops capacitor discharges through timing resistors

Alarm stays active until you turn it off.
A hidden touch point of two pinheads is all that you need.
Use a small capacitor at C1 (.1 uF) and it will appear to turn
off instantly (about a half second).
Or use a Push Button N.O. to instantly drain C1.