Lets talk about Frequency counters

ScottWang

Joined Aug 23, 2012
6,882
I was used the standard cmos ic as cd4518 and cd4511 to built a 6 digits 60Mhz frequency counter, when I need to measure the higher frequency then it will through the 74hc390 pre-divider and set up sample time as 0.1 second.
 

Thread Starter

Wendy

Joined Mar 24, 2008
22,138
Actually I messed up on th Time base th duration the gatting pulse needs to be 1 second which means it needs to me a .5 Hz time base.

0.5Hz TB.png
 

bertus

Joined Apr 5, 2008
20,456
Hello,

Perhaps a bit strange idea, but you could use a 4017 for timing latch and reset signals:

4017_timing_and_internal_schematic.png

You could use the carry signal for the counting gate.
Output 6 for the latch of the counter info to the display and output 8 for the reset of the counter.
You must clock the 4017 with 5 times the speed you want for counting time.

Bertus
 

Thread Starter

Wendy

Joined Mar 24, 2008
22,138
The 999999 Counter
I finally finished the schematic while I chose 6 digits it can easily be expanded or reduced.

99999 Counter.png
 
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Thread Starter

Wendy

Joined Mar 24, 2008
22,138
Things not discussed
If the time base had 1Khz to10KH freq this same coontercan measur a pulse width with minor modifications. Many instrument such as DVMsuse something like this . I am a bit surprised it too DVMs so long to add a freq counter funtion. Happy to see it though.

Guess baring brain farts I am done here. If I come up with a PCB I will tack it on. I also did not show an input conditioner. When I started this thread I was thinking of disp;ay for a funcion generator If anyone would like me to sketch one up please ask...
 
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Thread Starter

Wendy

Joined Mar 24, 2008
22,138
I could use a critical eye on this schematic. I may have confused Not .5Hz and .5Hz
 
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PaulDFL

Joined Jan 1, 2020
49
After decades in a junk box it's time for the rebirth. Cut the end off an old USB A to B cable and solder the 5vdc wires to the board. Check the power input for shorts and plug it in to a USB port for power.
It seems to know that time as passed (2001, I'm sure I built it in the early 70's) but the time-base is not working correctly (no output).


Found and fixed a few loose solder connection and adjusted the crystal trimmer for the time base.
Crystal-controlled multivibrator with series-resonant crystal.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720000155.pdf

Bingo, we have the correct frequency from the quartz crystal.

That signal goes to the first divider stage of 3 7490 counters (2 in divide by 5 mode, 1 in divide by 10 mode )
for a 1khz output that feeds into another counter stage.


That looks good. The rest of the circuit has a 7400 for the gate functions with a 7474, 7490 and 7492.
Can't remember exactly how that worked so I'll have to trace that circuit later.
Nice.
My counter also uses a crystal Time base.
I start with a 1 MHz oscillator, a divider chain for my gate signals; transfer and reset.
I’ll post a photo of my protoboard project.
 

nsaspook

Joined Aug 27, 2009
7,181
Nice.
My counter also uses a crystal Time base.
I start with a 1 MHz oscillator, a divider chain for my gate signals; transfer and reset.
I’ll post a photo of my protoboard project.
Why don't you post a schematic of your complete circuit instead of just a picture in your thread. If you don't have one, now is a very good time to start. You might even find the root of your problem. ;)
 

dl324

Joined Mar 30, 2015
10,520
I tried using those chips.
Couldn’t get those to work.
Where did you get your chips? I got mine in the 70's, long before counterfeiting from China became such a big problem.

I breadboarded the circuit about 30 years ago and it worked fine. Instead of using 7 segment displays, I used HP 5082-7300 displays:
1581618354514.png
They cost about $20 per display if you can find them.
1581618457981.png
 

MrChips

Joined Oct 2, 2009
20,884
Couldn’t get those to work.
We hear this so many times.
A circuit may fail to work for 1, 2 , 3, ... so many reasons.

First issue is "circuit does not work" means nothing to us except perhaps DOA or "dead as a nail".
There are different states of "does not work" which when described properly can be helpful in diagnostics.

Half the time the reason for a circuit not working is because the chip is being used incorrectly and the user failing to read manufacturer's datasheet.

When a circuit does not function correctly it is important to analyze the behavior functionally. With debugging a complex system having an oscilloscope and a circuit diagram is almost mandatory.
 

PaulDFL

Joined Jan 1, 2020
49
Where did you get your chips? I got mine in the 70's, long before counterfeiting from China became such a big problem.

I breadboarded the circuit about 30 years ago and it worked fine. Instead of using 7 segment displays, I used HP 5082-7300 displays:
View attachment 199006
They cost about $20 per display if you can find them.
View attachment 199007
I got mine from my distributor.
I
We hear this so many times.
A circuit may fail to work for 1, 2 , 3, ... so many reasons.

First issue is "circuit does not work" means nothing to us except perhaps DOA or "dead as a nail".
There are different states of "does not work" which when described properly can be helpful in diagnostics.

Half the time the reason for a circuit not working is because the chip is being used incorrectly and the user failing to read manufacturer's datasheet.

When a circuit does not function correctly it is important to analyze the behavior functionally. With debugging a complex system having an oscilloscope and a circuit diagram is almost mandatory.
I study the datasheet before I purchase the chips.
I used the schematic in the application section of the datasheet and wired it as shown.
I followed the function diagram carefully.
The schematic posted was the on I used from the datasheet.
 

PaulDFL

Joined Jan 1, 2020
49
I've done business with Jameco since around 1977. They don't have a very large selection these days, but they price match.
So have I for about the same time. :)
Jameco has most of what I need.
I go to Digi-Key or Mouser for the stuff Jameco doesn’t.
 

Reloadron

Joined Jan 15, 2015
5,358
Since someone resurrected an old thread, here's a 4 chip solution:
View attachment 199005
That circuit appeared in an old Engineer's Notebook II sold and distributed by Radio Shack and written by Forrest M. Mims III first printing 1982 pages 34 & 35. There is a three digit, half the complete version, also. I actually used it along with a reflective photo cell (LDR) circuit involving V to F. When I used it it worked fine. The V to F was a FV9400 I think. That was a long, long time ago. :)

Ron
 
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