# Frequency Meter CCT

Discussion in 'Homework Help' started by Elecmanic, May 12, 2010.

1. ### Elecmanic Thread Starter New Member

May 12, 2010
6
0
Hi to all, i am new to this board of which i have been suggested that i really could find help here.

I have been entitled to build up a simple digital frequency meter.

In poor words this meter should have a sample frequency as an input and should output the value on simple 7-segment displays.

This circuit should not be made for high frequency but it should be a bit accurate. The range should vary from 500Hz ~ 5kHz is enough.

This should be built using simple logic gates and ICs for example the 74HC192 counters and flipflops and similar once.

I really would like at least an overview on how to build this circuit and a simple circuit diagram in the shortest time possible if there somebody out there able to perform this task.

Thanks in advance for this help.
Hope to hear from you as soon as possible as it has a deadline date

Elecmanic

2. ### beenthere Retired Moderator

Apr 20, 2004
15,815
282
What you are trying to construct is a frequency counter - http://en.wikipedia.org/wiki/Frequency_counter

You need to condition the input to insure the internal logic gets triggered properly. The time base oscillator is what determines the accuracy.

3. ### Elecmanic Thread Starter New Member

May 12, 2010
6
0
Yes this type of counter... but i need a schematic of how it is built..

Thanks

4. ### beenthere Retired Moderator

Apr 20, 2004
15,815
282
It's simply a counter that allows an external input to count it up for a period of time. The time base determines the accuracy of the period. The simplest method is to gate the counter for one second, so the count is also the frequency.

It's conventional to latch the count into a register that is connected to the display, and update it every time the gate stops. Or you can display the count for a time, and then count up again, with the displays following the accumulated count.

You'll get extra points for using Dekatron or Nixie tube readouts. The 10 digit vertical neon tube readouts like HP used are uninspired.

This is pretty easy to do. If you have no background at all, Google turns up 135,000 hits on "ttl frequency counter circuits". Do your own and learn something.

5. ### Elecmanic Thread Starter New Member

May 12, 2010
6
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No i dont have a big background i am just a beginner and i really would like to see a schematic just to see an overview of what i should do thats all what i'm asking... my question is not to build it or to show the techniques how building it but to study other things!

Apr 20, 2004
15,815
282
7. ### Elecmanic Thread Starter New Member

May 12, 2010
6
0
its way far beyond my needs but still i cannot understand how can i build it with counters... i cannot find a suitable one using simple ttl ics on google :/