# 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.

#### 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.

#### bertus

Joined Apr 5, 2008
20,449
Hello,

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

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

#### 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.

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#### 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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#### 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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#### Rotman

Joined Jul 10, 2017
5
I could use a critical eye on this schematic. I may have confused Not .5Hz and .5Hz
Wendy.. could you message me. I have a question about a cord adapter you helped a guy with sometime ago. Thank you

#### 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.

#### PaulDFL

Joined Jan 1, 2020
49
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.
I’ll post it as soon as I can.

#### dl324

Joined Mar 30, 2015
10,486
The 999999 Counter
Since someone resurrected an old thread, here's a 4 chip solution:

Circuit from Motorola datasheet.

EDIT: Forgot to attribute the source of the circuit.

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#### PaulDFL

Joined Jan 1, 2020
49

#### dl324

Joined Mar 30, 2015
10,486
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:

They cost about $20 per display if you can find them. #### MrChips Joined Oct 2, 2009 20,870 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.

#### dl324

Joined Mar 30, 2015
10,486
I got mine from my distributor.
Is the distributor reputable? Companies like Newark, Mouser, and Jameco certify the authenticity of their parts. Companies like Tayda don't, but they claim they only buy directly from manufacturers.

#### PaulDFL

Joined Jan 1, 2020
49
Is the distributor reputable? Companies like Newark, Mouser, and Jameco certify the authenticity of their parts. Companies like Tayda don't, but they claim they only buy directly from manufacturers.
Yes.
I use Jameco most of the time.

#### dl324

Joined Mar 30, 2015
10,486
I use Jameco most of the time.
I've done business with Jameco since around 1977. They don't have a very large selection these days, but they price match.

#### 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.