1、It is a series resistor inside capacitor, using 100kHz to remove the impedance 1/(2*pi*F*C). 2、 The impedance become small, and we can then measure the true series resistor value. 3、 Using this theory, we can measure the capacitor is bad/ damaged or good in condition. 4、 Our ESR meter only applies less than 15mV DC or peak to peak on a good capacitor, as a result we can use it as in circuit test. 5、 During repairing TV, LCD, Audio board, etc. we can in circuit testing the capacitor is good or not. Features: It is a series resistor inside capacitor, using 100kHz to remove the impedance 1/(2*pi*F*C). The impedance become small, and we can then measure the true series resistor value. Using this theory, we can measure the capacitor is bad/ damaged or good in condition. Our ESR meter only applies less than 15mV DC or peak to peak on a good capacitor, as a result we can use it as in circuit test. During repairing TV, LCD, Audio board, etc. we can in circuit testing the capacitor is good or not. Dual terminal, for fast and easy inspect general capacitor or resistor, a printed ESR table for fast check. Specifications: Model MESR-100 Range Accuracy (After Zero, tested with 1,10,100R resistor) Refresh Time (Manual Mode) *Auto mode take 0 to 2s more time depend on value 0.000 to 1.000R 1%+2Digit 0.4s 1.000 to 10.00R 1%+1Digit 0.4s 10.00 to 100.0R 2%+1Digit 0.4s Accuracy Up to 1% (detail on above table) Wide Measurement Range: >1uF (for 0.1uF the error will be larger on equation 1/(2*pi*F*C) @ 100Khz ) High Resolution 4 digit, or 0.001Ohm @ 1 Ohm range Battery 2X AA 1.5V battery(not included) External Power 5V micro USB Battery Life time >80 Hours Operating current 0.02A Size 14.4*8.1*3.1cm/5.7*3.2*1.2in Weight Approx.219g/7.7oz Package List 1 * Capacitance Meter (battery not included) 2 * Test Clips 1 * User Manual