Digital clock using 555 timer

Reloadron

Joined Jan 15, 2015
5,499
You can try but I don't think a 555 timer circuit will afford the accuracy you would want. I am not saying it would not work, I am saying I see the 555 timer as a poor choice for the heart of a digital clock.

Ron
 

Thread Starter

Avijit Palit

Joined Jul 19, 2017
81
Schematics of what? I simply pointed out that in my opinion a 555 timer would be a poor choice as the oscillator employed in a digital clock. A simple Google of digital clock circuits will yield dozens of schematics. Some good and some not so good.

Ron
But there is no circuits to build a digital clock using only 555 timer.
555 timer can be used only for a simple counter.
 

Reloadron

Joined Jan 15, 2015
5,499
The 555 timer is just what the name implies, a simple timer integrated circuit for timing applications. That is all it is. Making a digital clock consist of several building blocks only one of which is an oscillator.

Post #2:
If you add some counters and 7 segment decoders.
You need other parts, a 555 timer alone will not make a digital clock. What you need to do is not just look at various digital clock circuits and schematics but also understand how the circuits work. That includes the oscillator to the display.

Ron
 

Thread Starter

Avijit Palit

Joined Jul 19, 2017
81
The 555 timer is just what the name implies, a simple timer integrated circuit for timing applications. That is all it is. Making a digital clock consist of several building blocks only one of which is an oscillator.

Post #2:


You need other parts, a 555 timer alone will not make a digital clock. What you need to do is not just look at various digital clock circuits and schematics but also understand how the circuits work. That includes the oscillator to the display.

Ron
What other ICs do I need to implement the clock?
 

WBahn

Joined Mar 31, 2012
25,904
But there is no circuits to build a digital clock using only 555 timer.
555 timer can be used only for a simple counter.
What is it you are trying to accomplish? A demo project for a class? A homemade clock to sit on an ego wall (basically, something you can point to and say, "I designed and built that back in the day.")? A clock that you will actually use to keep track of time?

Very different goals with very different requirements.

It's already been pointed out that a 555 timer as your clock oscillator is a poor choice, but if the goal is only to demo a project whose purpose is to show the ability to integrate several different functional blocks into a working whole, that might be good enough. The same for the ego wall.

But in any event you should have some idea of the impact of choice of oscillator.

Let's say that your 555 timer is, on average, just 1% off of the correct frequency. How much time would you clock drift each day? Is that acceptable? What amount of error IS acceptable?

Is a 1% error achievable with a 555 circuit? What's the best you can expect to average, over time, temperature, supply voltage, etc.
 

Thread Starter

Avijit Palit

Joined Jul 19, 2017
81
The 555 timer is just what the name implies, a simple timer integrated circuit for timing applications. That is all it is. Making a digital clock consist of several building blocks only one of which is an oscillator.

Post #2:


You need other parts, a 555 timer alone will not make a digital clock. What you need to do is not just look at various digital clock circuits and schematics but also understand how the circuits work. That includes the oscillator to the display.

Ron
What is oscillator?
 

Thread Starter

Avijit Palit

Joined Jul 19, 2017
81
What is it you are trying to accomplish? A demo project for a class? A homemade clock to sit on an ego wall (basically, something you can point to and say, "I designed and built that back in the day.")? A clock that you will actually use to keep track of time?

Very different goals with very different requirements.

It's already been pointed out that a 555 timer as your clock oscillator is a poor choice, but if the goal is only to demo a project whose purpose is to show the ability to integrate several different functional blocks into a working whole, that might be good enough. The same for the ego wall.

But in any event you should have some idea of the impact of choice of oscillator.

Let's say that your 555 timer is, on average, just 1% off of the correct frequency. How much time would you clock drift each day? Is that acceptable? What amount of error IS acceptable?

Is a 1% error achievable with a 555 circuit? What's the best you can expect to average, over time, temperature, supply voltage, etc.
I am just learning the concept
 

WBahn

Joined Mar 31, 2012
25,904
What is oscillator?
I don't know how fluent your English is, but the word "oscillate" means to move back and forth with regularity. It is used in "everyday" English (though I don't know how commonly) in a sentence like, "His reaction upon seeing that his rescuers were also his enemies, oscillated between relief and despair."

It has basically the same meaning in engineering -- something that regularly transitions between two extremes. Like the pendulum on an old clock. In electronics, it is usually a circuit that repeats a simple pattern continuously, such as a sine wave or a square wave. A largely synonymous term is "clock".
 

WBahn

Joined Mar 31, 2012
25,904
I am just learning the concept
What concept? There are many concepts that you could be focusing on -- and similarly several concepts that you could be focusing on but probably aren't (yet, at least).

Hard to help you achieve your goals unless you can articulate what those goals actually are.

The good news is that the exercise of figuring out how to articulate your actual goals often goes a long way toward seeing a viable path to follow in pursuit of them.
 

Thread Starter

Avijit Palit

Joined Jul 19, 2017
81
I don't know how fluent your English is, but the word "oscillate" means to move back and forth with regularity. It is used in "everyday" English (though I don't know how commonly) in a sentence like, "His reaction upon seeing that his rescuers were also his enemies, oscillated between relief and despair."

It has basically the same meaning in engineering -- something that regularly transitions between two extremes. Like the pendulum on an old clock. In electronics, it is usually a circuit that repeats a simple pattern continuously, such as a sine wave or a square wave. A largely synonymous term is "clock".
Sorry for stupid english. My english is little rusty.
 
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