DT4282 AC voltage range Input impedance ?! - Page 1
Forum section: electronics / testgear

author: nanosmart
author_rank: Newbie
timestamp: January 06, 2020, 09:16:35 pm
content: Hi every one, I read in the specification of DT4282 that input impedance of AC+DC and AC range is about 1Mohm. Is it true?! and if it's, Cloud some one please explain why? why not 10Mohm like other multimeters that hioki designed?In page 82 of official user manual, it mentioned that input impedance is about 1Mohm in AC voltage range.

author: HKJ
author_rank: Super Contributor
timestamp: January 07, 2020, 05:50:23 am
content: THe 1Mohm is correct, you can see more about the meter in my review (including a tear-down):https://lygte-info.dk/review/DMMHioki%20DT4282%20UK.html

author: nanosmart
author_rank: Newbie
timestamp: January 07, 2020, 02:10:22 pm
content: Thank you. the build quality and design of this meter is one best on the market, but i couldn't find a reason why it has 1Mohm input impedance on AC and AC+DC. they could have used 10Mohm for AC and 1Mohm for AC+DC, but for some reason they didn't!

author: hgjdwx
author_rank: Regular Contributor
timestamp: January 08, 2020, 06:48:26 am
content: I have a DT4282 that has been in use for more than two years.The DT4282 has many advantages. Some of its properties are unmatched by other multimeters.Like its DCV range and resistance range speed, resistance range accuracy, and stability, temperature drift and so on.There is 1uV resolution and stability of the DCV I appreciate and often use.There is also a very good frequency response of its ACV.And its ultra-fast PEAK function.The above mentioned are far superior to other hand-held multimeters of the same grade.But I also see many disadvantages it is:It does not have an analog bar, the continuity test response time is 10mS, the display shows dark,Only voltage AC+DC function, no current AC+DC function, AC voltage, current speed is not fast,Capacitance is very slow, and AC voltage and current mantissa are forced to zero within the word is below "999".Large reading range when the signal above 100 KHz for ACV measurements, and the upper limit for frequency measurement is 500 KHz, andThe frequency of many test signals cannot be displayed, and sometimes the manual switching range does not respond.PEAK function does not have mV range, AC+DC and AC/DC dual display have no mv range.The FILTER function has only 600V and 1000V range and no 6V and 60V range.The recalled stored data and current measurement data cannot be displayed in the same screen.So I made the following suggestions to the manufacturer:Functional improvements:1: Continuity test response time increased to 1ms, and Increase resolution to 0.01OHM2: Use high-brightness, high-contrast display (just now display is dark)3: Diode range increases resolution to 0.0001V4: Open circuit of resistance range is changed to "OL" without flashing5: Increase the measurement speed of the capacitor6: Cancel auto-zero function in “999” character of AC range7: Increase the AC speed and AC/DC dual display measurement speed, and instead when performing AC/DC dual display automatic speed measurement, the ranges of AC and DC are not related and the ranges are independent.8: Improve the reading stability of the signal above 100KHZ by ACV (currently the reading is too large)9: Increase the upper limit of the frequency measurement range and improve some frequencies can not be displayed10: Improvement Sometimes transform Range Does Not Respond11: Improvement: The “?”, “?” and “RANGE” keys on the right side of the panel together constitute the quick function key for range switching, similar to the desktop multimeterIncreased functionality:1: PEAK function increases mv range2: increase the recalled stored data and the current measurement data with the screen display3: FILTER function increases 6V, 60V range4: Increase the low impedance mode function5: Add analog bar display6: Increase range indication7: increase the maximum, minimum, present value (real-time measurement) with the screen display8: increase the positive peak, negative peak, present value (real-time measurement) with the screen display9: AC+DC and AC/DC dual display increase the mv range10: Add current AC+DC function.11: Add automatic power off time setting function.