how can I do counter and timer by OP AMP (not by using Flip Flop)
thanks

 

You can't.

 

What are you counting and what are you doing with the result? Digital display, analog meter, audio or lights, etc.?

ak

 

You can configure an opamp as an oscillator to create pulses, then integrate (i.e. effectively count) the pulses. The pulse frequency and number of pulses determine the time it takes for the integral to reach a threshold voltage.

 

Why do we have to using a hammer to scoop water, and using a spoon to beat the Iron plate.

 

As analogies go, I think you're a little wide of the mark. Maybe what you are asking is why some people still insist on painting with brushes rather than do it on a computer. Or shooting pictures on film. Or producing music on vinyl.

Exploring other, or just older ways of doing things is a part of learning, a part that sadly is more and more out of favor these days. Also, the existance of newer tools or methods does not obsolete instantly all of the characteristics of the previous constructs. I'm not saying that the new ways aren't "better." I'm saying that they are not identical.

Among the many people on the innergogle that sell clock kits, three interest me. One guy's clock is all digital, and all discrete. Not one IC in the entire thing, the pc board is large and so well laid out that it is art. Next is a digital clock in a uC <snore> with two D/A outputs driving analog meters, one for minutes and one for hours <awake>. But the crown goes to the analog clock - a digital display with 100% opamps driving it. I've lost the link to that one, but I love the idea not because analog anything is better than everything <gasp>, but because it exemplifies a different view of reality.

There is art and life in the alternatives. Life is choice.

ak

 

Well, you could easily make logic gates from opamps, then proceed with a digital desgin.

Bob

 

how about we feed in the pulses on one edge of the summing amplifier setup and get the other input to the summer output.
thereby,
first pulse 1+0=1
second pulse 1( the voltage input of one pulse )+1( the previous output, that is the one standing )=2 ( the resulting output )
so, the net voltage output increases step by step as many pulses we feed in.
Please tell if it is valid or not, doesnt matter if unnecessary or necessary. Is it possible ?

 

The left side of the circuit above does something close to what you asked about. It was designed in about 1980 when the answer for every problem seemed to be analog, in this case it was a box on the screen of a television camera viewfinder that needed to change in size as the zoom lens zoomed in and out.

The two opamps generate staircase of pulses -a ramp worked but it jumped around a lot because of noise, so the steps are bigger than the noise and the displayed box appeared stable. The staircase if fed to a compartor (100) which detects when the stairsteps exceed the voltage on the comparator's non-inverting pin. All you really need is one opamp and one comparator and if you are lucky the timing will be (more or less) predictable.

An even simpler way of making a long and precision timebase was to use an NE555 as an astable multivibrator tuned to a frequency just below that desired and inject some low amplitude pulses to pulse the control voltage pin, resulting in injection locking to oscillator to a harmonic of the timing pulses. This is known to some as injection locking. The attachment is a series of slides about injection locking.

 

Hola Souvik
This thread is dated 2014.

 

The poor guy had to wait 14 years for us to finish answering him. We need to get better at this.

 

No, no. Only 6½ years.

 

Why is a 6 1/2 year old thread being resurrected at all?????

 

I stand corrected. Maybe we should consider whether allowing long dormant threads to resurrected (or should I say reawakened?
)

 

I stand corrected. Maybe we should consider whether allowing long dormant threads to resurrected (or should I say reawakened?
)

Is this another task for the mods to shoulder -- they do quite a bit as it is. They could either allow the thread to be resurrected, or they could simply start a new thread with a link to the old one. Maybe there is a volunteer, as the newest mode to take on this burden.

 

How about an automatic function that after the thread is over some age that the date becomes a larger font in a more solid color? That could be an automatic function not needing a volunteer.
OR, just make all of the post dates/times a more obvious font that stands out better than what we have now?

 

Some times it might be useful to open again a necro-thread.
For instance, Dick’s example of the automatic screen box.

But a better strategy would be to link the necro thread instead.