Products > Test Equipment

AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter

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stj:
any chance of the rest of the schematic?
i'm curious about the star on the resistor and the function of the jumper.

crazyguy:

--- Quote from: stj on July 19, 2017, 04:46:34 pm ---any chance of the rest of the schematic?
i'm curious about the star on the resistor and the function of the jumper.

--- End quote ---

RLD is the signal input pin, i.e. short the jumper in NCV measurement

I think the resistor value (10M) is not that critical. It just connect the antenna to the ground.




barry14:
I received my AN8008 21 days after buying it on Ebay.  Shipped from China.  I paid $10.00 for it plus $4.34 for shipping, or a total of only $14.34.  For that price, it is a  remarkable meter.  I checked it on most ranges and functions and it easily meets its specifications, usually much better. It comes with 2 sets of test leads and a wide range of tip adapters. The built-in stand is flimsy but usable.

floobydust:
NCV measurement from the AC voltage signal into the RLD IC, the measurement results show five grades, 0 ~ 50mV display EF, 50 ~ 100mV / 100 ~ 150mV / 150 ~ 200mV / 250mV or more to 4 show a '-' character (adjustable) and with(?) the rhythm buzzer sound.

Applications need to be adjusted according to the value of Rx and the induction line. NCV measurement and the minimum resolution that can be set E2 (In 0.1mV): 25h (H) & 24h (L) set in base NCV measurements, 27h (H) & 26h (L) NCV resolution setting,
Calculated as the measured value :( - in base) / = 0 ~ 4 Resolution (rounded result), the count is greater than 4. 4. Such as:
25h (H) & 24h (L) = 0064h, 27h (H) & 26h (L) = 0096h, measuring the induced signal = 50.0mV, then LEVEL = (50.0-10.0) /15.0~=2, the display section 2 '- -. "

Optional PT1.2 NCV function as a control indicator (E2 provided F9h.bit0 = 1). When no signal PT1.2 = 0, a letter.
When the number PT1.2 with buzzer output, buzzer PT1.2 = 1, and 0 otherwise. This setting has no effect on other functions, PT1.2 = 1.

floobydust:
I spent time reverse-engineering and figured out the schematic but the IC (die) pinout a bit different than DTM0660. The actual MCU must be the same family but with better A/D resolution and external Vref.
My guess is Dream Tech International writes the firmware for the multimeter MCU.

From Russian AN8008_1715xxxxx EEPROM dump I can see unused functions- such as temperature measurement, hFE, middle current, non-contact AC voltage detection (NCV) etc.
Should be possible to enable some eggs.

I could not find a UART TX line. I think the die-bonding wire is not brought out  :(

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