Difference between revisions of "Frequency Counter"

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* Difference = 500 Hz or 0.1% accuracy
 
* Difference = 500 Hz or 0.1% accuracy
 
* Can only adjust the variable capacitor in narrow range
 
* Can only adjust the variable capacitor in narrow range
* Freq = 25,000 MHz - measured = 24.997 MHz
+
* Freq = 25,000 MHz - measured = 24.997 MHz
 
** Error = 3 KHz / 25,000 KHz = 0.012%
 
** Error = 3 KHz / 25,000 KHz = 0.012%
 +
* Freq = 10.000 Hz - measured = 9.999 Hz = .01% error
  
 
== Reviews / Builds ==
 
== Reviews / Builds ==

Revision as of 14:52, 3 October 2020

FreqXounter-Kit-Assembled-02.PNG

Features

Built into case

  • P-Touch white on black labels

FreqCounterLabels.jpg

Plastic 100x60x25mm-720px.jpg

Power 5-1mm.PNG

  • 7-9V in
  • Right angle header pins pointing to inside of card
  • 4-40 x 3/16” Machine Screws
  • 4-40 Standoffs

FreqCounter-Case-11-720px.jpg

Rework - Add Pre-Amp

  • Re-uses extra HF transistor that would have been used by crystal tester oscillator
  • AC coupled input
  • Based on

Pre-Amp schematic

FreqCounter PreAmp Schematic.PNG

When building kit, do not install

FreqCounter DoNotInstallParts.PNG

Cuts/Jumpers

  • Four cuts
    • Blue = 1 front side cut
    • Green = 3 back side cuts
  • Jumpers Red

FreqCounter Rework PCB Front.PNG

  • Green = Back side cuts

FreqCounter Rework PCB Back.png

  • Short etch on one cut

FreqCounter Rework-Cuts-Back.PNG

  • Details of preamp input pin

FreqCounter Rework-06.PNG

  • With parts

FreqCounter Rework-07.PNG

  • Wire on back

FreqCounter Rework Wires Back.PNG

Testing

FreqCounter InCase.jpg

  • 4.9152 MHz crystal
  • Scope frequency counter shows 4.19520 MHz
  • Freq Counter displays 4.9747 MHz
  • Difference = 500 Hz or 0.1% accuracy
  • Can only adjust the variable capacitor in narrow range
  • Freq = 25,000 MHz - measured = 24.997 MHz
    • Error = 3 KHz / 25,000 KHz = 0.012%
  • Freq = 10.000 Hz - measured = 9.999 Hz = .01% error

Reviews / Builds