Part three of a full build of this moderately easy electronic kit, a 5-digit frequency counter and crystal tester. This third part includes testing and a bit of history behind the design.
Wolf's website: http://www.qsl.net/dl4yhf/freq_counter/freq_counter.html
Wolf's website: http://www.qsl.net/dl4yhf/freq_counter/freq_counter.html
Hi, I really enjoyed your video, I bought this kit to make a display unit for an HP audio oscillator, I didn't think for a second about testing the crystals – I do this with a simple shielded fixture, an oscilloscope and a generator. Since the kit is on the way I couldn't do the analysis like you and I'm glad for it, I will convert the crystal testing circuit to an input amplifier. Thanks for the inspiration, I don't need to finish the input amplifier outside the board.
Nice day 🙂 Tom
Great job on the build and review. Are you now going to make fourth video showing how the circuit can be improved for the crystal checking circuit. It would be great if you can.
maybe a 358 and Pwr pigtail hat/shield thing that plugs into the pin header, amplification and power plug and play. Good show, yes the thing sucks. Three extra 22p and a resistor. Your right about it being a Ham creation. It could be usefull for the original purpose, without the xtal part.
For me the crystal tester was 65 kHz off, but then I found that by pressing the button (which you've not soldered in), and selecting Zero option (when no crystal is connected) makes the device "zero" itself, and starting from that point my crystal measurements were spot on.
Also I found that it completely ignores crystals of certain frequencies, such as 6 MHz, 4 MHz and 32.768 MHz. I guess it's a technical limitation.
Otherwise, cool little device and actually useful (I bought it as a crystal meter, and it works very well – for frequency counting I have enough scopes).
I'm powering it with a 9v bench power supply.
As shown, the xtal osc has several issues with temp drift, starting with the disc capacitors being notorious for value-temp drift ..
See TheHWcave mod to replace/convert the xtal tester to a preamp that allows a lower input level of about 1.5 mV P-P (significant increase in sensitivity) when using 8V power supply.
The schematic for the oscillator seems very close to one that I remember having seen in a Elektor book (300 Circuits or 301 or something like that). I am not sure about the values but the schematic was the same (as long as I remember correctly). It was a crystal oscillator circuit to test the quartz crystals. They suggested another stage after it that acted as a detector with an LED as indicator that is oscillating and the output of the oscillator they suggested that can be read by a frequency meter to see the frequency.
its no good at the bottom because it may use an integral count, but it might be perfect for an integer count of hits.
It may be "awful", but maybe there's just one bad component?
Excellent!!! Very well explained.
Thanks a heap for this wonderful video presentation.
I built mine and the display is blank.
If you get close to touching the pic chip crystal the display bursts into life.
Going to start by swapping the trimmer.
I ordered a kit exactly like this from China and its on its way so watching these you tube videos about it (such as yours) are so useful in that I might pick up some hints and tips on building and using it. So, please tell me, sir, what is the variable capacitor for? is there a need to fine tune the kit? Is that what is the variable capacitor for? Thank you.
Nice work Julian, good tests !
The best video on the freuquency counter!! YOU ARE THE BEST!!!! You really do a thorough review highlitign all the characteristics. The question I had (and that you answered) was: What is the max voltage I can apply to the frequecy counter's pins without blowing up the PIC? and that would be 5V. Thanks! 🙂
I know I am 2 years late,
But for those who work on this kit now – just connect the far left leg to your low voltage signal source- with no modification to the circuit- it will work fine as preamplifier !
Just don’t forget the ground..
Does it have Any use for working on old tube radios