I purchases this to calibrate a precision 200 I want to rebuild. nice device to have around if needed. Anyone know anything about this? I have no info, schematic, manual, zip. There is a adjustable capacitor I suspect is for calibration? Anyone have any ideas? thanks
this is some post info from sellers/buyers
This is from the ebay seller page.
HUABAN
Manufacturer model: HXJ10005
• Product Type: Crystal Oscillator Frequency Counter
• Frequency Range: 1Hz-50MHz ; Crystal Test Range: about 4MHz-48MHz(not include 32.768KHZ)
• Power supply : USB 5V or DC 5-12V ; Digits Resolution : Five
• PCB Size: 80*53*2mm. Net weight : about 39g
• Package Include: 1 set Frequency Counter Tester Parts( Attention: the products are in parts , the buyers need to assemble them)
Amazon info the same. Below interesting feedback from a buyer.
The kit took couple of weeks for delivery. Neatly packaged with all parts plus a few extra. Nice PCB with component values indicated on board via silk screened labels. No directions otherwise of how to use. I assembled board and originally used a combination of a uA7805 connected to a power module for the supply but it did not work properly; apparently voltage too low, so I then used a variable bench supply at 5V at the jack input, so both oscillator and processor were at 5V. I removed the capacitor between the test crystal oscillator and put in a jumper, so that the processor input would not drop below the maximum negative voltage at the input pin. The unit appears to be now working properly when tested with several different crystal frequency values. If I was using a higher voltage at the jack, I would not remove the capacitor, but I would put a Schottky diode (cathode) on pin 3 of processor with anode grounded, to keep the pin from going too far negative.
ZL2PD indicated on his website that the oscillator waveform can exceed the maximum input to the pin on the PIC chip, if the oscillator supply (voltage at the power jack) is higher than the 5V on-board regulator provides to the processor. Since the oscillator normally uses a capacitor to couple to the processor input, there is also the potential problem that the negative voltage seen by the input pin can exceed the maximum -0.3 volts allowed. It is difficult to say how the processor would tolerate any input voltage level violation, so this may be why the same kit (that shows up by different vendors on Amazon) gets such mixed ratings; some worked, some did not.
this is some post info from sellers/buyers
This is from the ebay seller page.
HUABAN
Manufacturer model: HXJ10005
• Product Type: Crystal Oscillator Frequency Counter
• Frequency Range: 1Hz-50MHz ; Crystal Test Range: about 4MHz-48MHz(not include 32.768KHZ)
• Power supply : USB 5V or DC 5-12V ; Digits Resolution : Five
• PCB Size: 80*53*2mm. Net weight : about 39g
• Package Include: 1 set Frequency Counter Tester Parts( Attention: the products are in parts , the buyers need to assemble them)
Amazon info the same. Below interesting feedback from a buyer.
The kit took couple of weeks for delivery. Neatly packaged with all parts plus a few extra. Nice PCB with component values indicated on board via silk screened labels. No directions otherwise of how to use. I assembled board and originally used a combination of a uA7805 connected to a power module for the supply but it did not work properly; apparently voltage too low, so I then used a variable bench supply at 5V at the jack input, so both oscillator and processor were at 5V. I removed the capacitor between the test crystal oscillator and put in a jumper, so that the processor input would not drop below the maximum negative voltage at the input pin. The unit appears to be now working properly when tested with several different crystal frequency values. If I was using a higher voltage at the jack, I would not remove the capacitor, but I would put a Schottky diode (cathode) on pin 3 of processor with anode grounded, to keep the pin from going too far negative.
ZL2PD indicated on his website that the oscillator waveform can exceed the maximum input to the pin on the PIC chip, if the oscillator supply (voltage at the power jack) is higher than the 5V on-board regulator provides to the processor. Since the oscillator normally uses a capacitor to couple to the processor input, there is also the potential problem that the negative voltage seen by the input pin can exceed the maximum -0.3 volts allowed. It is difficult to say how the processor would tolerate any input voltage level violation, so this may be why the same kit (that shows up by different vendors on Amazon) gets such mixed ratings; some worked, some did not.
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