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ESR Meter - Model: MESR-100                               BUY Here
​MESR-100 AutoRanging In Circuit ESR Capacitor /Low Ohm Meter Up to 0.01 to 100R

JINGYAN MESR-100 Autoranging capacitor ESR and Low Ohm Meter
Measuring range from 0.01 to 100.0R, support IN CIRCUIT Testing.
Using true 100KHz square wave to measure the ESR value, which is equal to the testing method of capacitor manufacturer.
In the market, there is some technique using short pulse method to testing, but the value will be varying vs the capacitance and sometimes reading is different from the manufacturer's value.

What is ESR of capacitor?
There is a series resistor inside capacitor, using 100kHz to remove the impedence 1/(2*pi*F*C), the impedence become small, and we can then measure the true series resistor value.
A bad E-capacitor will have larger ESR and create large ripple rather than filering noise. Normally it is smaller then 1 ohm.
Using this theory, we can measure the capacitor is bad/ damaged or good in condition.
Because our ESR meter only apply less than 15mV DC or pk to pk on a good capacitor, so we can use it as in circuit test. Because this low voltage, it can not turn on the semiconductor inside a circuit under testing.
During repairing TV, LCD, Audio board, etc. we can in circuit testing the capacitor is good or not.

Recent customer review by Preher-Tech : March 2013.​​

*Dual terminal, for fast and easy inspect general capacitor or resistor, a printed ESR table for fast check
Range               Accuracy (After Zero, test with 1,10,100R resistor)             Refresh Time (Manual Mode)
                                                                                                                             *Auto mode take 0 to 2s time depend on value
​0.00 to 1.00R                               1%+1Digit                                                                             ~0.3s
​1.00 to 10.00R                             1%+1Digit                                                                             ~0.3s
​10.0 to 100.0R                             2%+1Digit                                                                             ~0.3s


Accuracy: Up to 1% (detail on below table)
Wide Measurement Range: >1uF (for 0.1uF the error will be larger on equation 1/(2*pi*F*C) @ 100Khz )
High Resolution: 0.01Ohm
AUTO/ manual mode:
i) Auto Range:
Press and release the Range button and at the first line of LCD will show “AUTO:"
At auto mode meter will automatically select the best range to detect.

ii)Manual Range:
Scroll the manual range from 1R, 10R and 100R range,
In LCD will show 0-1R, 1-10R and 10-100R.
1 Key Zero:
Short circuit the testing terminal, cancelling the wire resistance.
Long press and hold the “ZERO" button for 5s, LCD shows “ZERO" and wait the zero disappear.

While power up LCD shows the “ESRMETER V1.0"for 4 seconds, within these 4 seconds, user can press the “Range" button to switch backlight on/ off
Low Battery Detection: For battery used up 85%, LCD will show “LO BATT"flashing in LCD first line, user should replace a new battery to operate.
Power: 9V battery
*PLEASE DISCHARGE THE CAPACITOR BEFORE TESTING, you can use a screwdriver to short circuit, or series with a resistor around 10 ohm and short for 5 to 10s.
There is 2 fast diode inside the meter to prevent high voltage, but it is important to discharge the capacitor firstly, as it is a large surge current and voltage and may damage the meter.