Часть обзора переведена автоматически.
Frequency measurement: I managed to run it only if the input signal is between 4.7 and 5 volts (not to be exceeded). The signal goes directly to pin 3 of the PIC (5V max). An incoming signal amplification circuit must be provided. Quartz measurements: Very poor circuit. It depends a lot on the supply voltage, the temperature and the quartz frequency. Limited use. Measurement examples: (3,2748 MHz -> 0) (4,9152 MHz -> 4,9166) (16 MHz -> 16,001 16,006) (20 MHz -> 20,007) (22 MHz -> 22,007). Strange situation: if the power is about 9 volts, the 4.9152 MHz quartz give these results: -> 14,667 14,669 14,672 14,681 Third harmonica?) Under investigation.
This came with no instructions, but the PCB is labelled with component values so I found it very easy to assemble. A description of how to use the add/subtract functions can be found at http://www.qsl.net/dl4yhf/freq_counter/freq_counter.html (as mentioned by tom_pin in the product discussion). The display is much easier to read if you add a red filter. If I had the chance to make 1 change, I'd provide space on the PCB for 4mm sockets for ground and frequency signal in; then it would be easy to connect different sorts of test lead (e.g. pointy or spring hook).
It says to adjust the xtal frequency to 20.000 MHz. But doesn't say how. I would like to know how. Other than that, mine works excellently.
I bought two of these and have just put one of them together and it works a treat. I've got a box of crystals, collected over the years from old equipment and so on - In most cases, it displayed a couple kHz off from what the crystal was marked as. You can adjust it to a known exact frequency with the trimmer-capacitor. A friend of mine says he has some 32 kHz clock thingies that is are a damned sight more accurate than the crystals, so we can adjust it with that. crystal marked => read 4.000 MHz => 4.0000 MHz 6.000 MHz => 6.0008 MHz 9.04933 MHz => 9.0496 MHz 14.31818 MHz => 14.323 MHz 52.416 v=> 17.4something MHz * 1/3 of the fundamental It is well laid out, with all the components clearly marked on the PCB. Lack of any documentation is a small negative point, but not a problem, so still 5 stars. There is an extra 22p capacitor which I thought was spare, but in an earlier comment, someone has written a document for it, showing that the extra capacitor can be used if the low frequency readings are unstable. The construction is very straight forward and the other kit I bought will be my nine year old son's first soldering project :) Delivery was also very fast. It was marked as out-of-stock until 05/02/2015, but mine arrived on 10/02/2015.
Very easy to construct and test. Worked excellent first time after tuning. Good quality components and very high quality PCB. Good stability and good accuracy once setup. If I did have one grumble then it would be the quality of the variable tuning capacitor. Its very sensitive and would benefit from a slightly better quality capacitor to make sure it is accurate all the time, apart from that Excellent. I love it. Well done BangGood, another brilliant product that every toolbox should have, from the Radio Amateur like myself to the novice.
High Quality DIY Frequency Counter and Crystal checker. Works perfect !! Testing a 8700.000Hz crystal and a 50Hz input signal. See Pictures. Recommended !!!!
Perfect to read frequency.. For the the price I pay I am very satisfied...
Quite simple to build, useful but not always precise in the measure of quartz
Thank YOU Please I did pay in September the RK560 frequency counter meter . Take pictures Photos the Bill Ticket that It did pay in date September 2018. I will wait the RK560 Frequency Counter Meter . Please read see pictures Photos the Bill Ticket. Thank YOU BANGGOOD very very much BANGGOOD.
Bon KIT