Difference between revisions of "Frequency Counter"
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* Re-uses extra HF transistor that would have been used by crystal tester oscillator | * Re-uses extra HF transistor that would have been used by crystal tester oscillator | ||
| + | * AC coupled input | ||
* Based on | * Based on | ||
Revision as of 12:40, 3 October 2020
Contents
Features
- Original Design by DL4YHF
- Frequency range: 1 Hz-50 MHz
- Crystal Test Range: 4 MHz-48 MHz - Replaced with pre-amp circuit
- PCB size：8*5.3cm
- Fits in 100 x 60 x 25 mm enclosure
- Source - AliExpress Frequency Counter - Very inexpensive
- PIC-freq.counter-modification
Case
- P-Touch white on black labels
- Inexpensive plastic case
- Plastic Waterproof Cover Electronic Project Instrument Enclosure DIY Box Case Junction Box Housing 100 x 60 x 25 mm Black
- BNC connector - female chassis mount
- 5.1mm Chassis mount power connector
- 7-9V in
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
When building kit, do not install
Cuts/Jumpers
- Front side cuts - blue
- Jumpers Red
- Back side cuts
- Details of preamp input pin
- With parts
Testing
- 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
Reviews / Builds
