#Digital clock mini project generator#
#Digital clock mini project driver#

When all four nibbles of stored/latched data equal the directly connected four nibbles of data, pin 6 of all 74LS85 ICs goes to logic 1 state. These nibbles directly connected and latched ones are compared. The latched nibbles are connected as one set of 4-bit data inputs to magnitude comparator ICs 74LS85, while the other set of 4-bit data (BCD output from IC3 through IC6) are directly connected to comparators as shown in Fig. The reason behind doing so is to latch (store) by momentary depression of press-to-on switch S3.

Each nibble (4-bit sequence) of BCD data from IC3 through IC6 of the first part of the clock circuit is connected to IC11 and IC12 (two nibbles to each of these ICs). Major components of this circuit can be enlisted as two 74LS373 octal ‘D’ type transparent latches (IC11 and IC12), four 74LS85 4-bit magnitude comparators (IC13 through IC16), one 74LS21 dual 4-input AND gate (IC17), and Darlington pair comprising transistors BC547 (T1) and SL100 (T2).

#Digital clock mini project driver#

which comprises preset time storage, magnitude comparator, and relay driver part. The circuit design of the second part is clearly illustrated in fig.2. Preset time storage, comparator, and relay driver circuit. With this arrangement of switches, the clock can be set to display any desired time between zero hours and zero minutes to 23 hours and 59 minutes. These switches are used for quick adjustment of minutes and hours count respectively. We can see in the figure, that the 1Hz clock is also connected to one of the poles of push-to-on switches S1 and S2. To solve this, Decoupling capacitors of 0.1♟ each have been used between Vcc and ground of all ICs. Circuit noise can rise as a major problem in the operation. The BCD outputs of IC3 through IC6 marked A1 through A4, B1 through B4, C1 through C4, and D1 through D4 respectively, are also connected to various IC pins (Fig. The clock gets reset at 24 hours count and for this reason, the maximum time that would be displayed by the clock is 23 hours and 59 minutes. In response to this, the 7-segment common-anode displays DIS1 is driven through DIS4 respectively. The BCD to 7-segment decoders IC7 through IC10 is used to decode the BCD outputs of IC3 through IC6. IC pair 5 and 6(IC5-IC6) is set such that it resets themselves on reaching a count of 24. And, so the output of IC4 connected to clock pin 14 of IC5 has a pulse recurrence frequency of one hour. Similarly, following the connection pattern of IC1-IC2, the IC3-IC4 pair is wired likewise.

Thus the output of IC2 connected to clock pin 14 of IC3 has a pulse recurrence period of one minute. During this course, IC1 serves as a divide-by-10 counter and IC2 as a divide-by-6 counter. The output obtained from both of the above-mentioned circuits become more accurate with the fact that both circuits take advantage of 32.768kHz quartz crystal.Įach ICs are designed/wired with a particular task to perform.

#Digital clock mini project generator#

1 Hz clock generator circuit is shown in the button of the article. A 1Hz clock is used to supply the input to the IC1 through pin 14. In addition, passive components like few resistors, capacitors, and push-to-on switches are employed. For this purpose, this circuit makes use of six 74LS90 decade counters (in the figure, IC1 through IC6), four 74LS247 BCD to 7-segment decoders/drivers (IC7 through IC10), and four LT S542 common anode displays (DIS1 through DIS4). This section is designed to display the time in hours and minutes format and is wired such that it functions in 24-hour mode. shows the circuit of the 24-hour digital clock section.

Preset time storage, comparator, and relay driver circuit.įig.

The entire circuit can be divided into two main parts.

Talking about the circuit components, it uses discrete ICs which are commonly available.Ĭircuit Description of 24-hour Digital Clock and Timer Circuit.

After storage of the time as mentioned above, the clock is set to display the real-time (in 24-hour mode) and it serves our purpose.

The time at which the device or load is to be switched ‘on’ or ‘off ‘ can be electronically stored while being displayed simultaneously.

When using this circuit as a timer/an alarm.

This circuit can be used for two purposes: both as a timer and a 24-hour clock.

Arduino Digital Clock using DS3231 Pi Moduleįeatures of 24-Hour Digital Clock and Timer Circuit.

Digital Clock with Second and Alarm Time Display.

Various Other timer and clock circuits are posted in