50MHz frequency counter
This is one nice frequency counter developed by Peter Cousen. This is really low cost frequency counter as it uses elements available world wide.
The frequency meter can measure frequencies with 1 Hz resolution when measured frequency is up to 100kHz. Other features include:
- Auto-ranging with floating decimal point.
- Up to 7 digits displayed.
- Auto-adjusting gate speed (0.1 sec to 1 sec).
- Simple, ease to assemble, and highly stable readout.
- Sensitivity approximately 100 mV RMS (100 Hz to 2 MHz), 800 mV RMS @ 50 MHz.
- Input overload protected.
Circuit and firmware are available for download. You may want to check out modified version which allows counting up to 80MHz.