•High-speed single chip computer is used for voltage sampling test, and LED lamp is driven to display voltage (unlike other products on the market, which use purchased voltmeter and are installed separately), so as to realize the integration of boards and cards and reduce the defective rate (due to constant current, only voltage display function is used) •0-300V adaptive voltage, suitable for most series-parallel lamp bead tests. During the test, the gradual start mode is adopted, the voltage is automatically adapted, the current is gradually increased, and the lamp bead will never burn, and the normal brightness can be reached after three to five seconds. The positive and negative poles of the lamp bar and the lamp bead are connected reversely, without burning the lamp bar and the lamp bead •Digital display of real-time voltage output, with adjustable voltage inside, the voltage value can be self-corrected. The digital meter uses green LED. The display of 00 indicates short circuit and 300V indicates open circuit. The display voltage of each group of LED light bars of the same LCD TV should be the same •Cold and hot isolation, never electric shock. Integrated design of power cord and machine box, convenient to carry out •You can light up the LCD TV screen without removing the screen. (The LCD TV is usually divided into several groups in parallel. The voltage can be used to determine which group of LED lamp beads are damaged.) •During the test, do not look directly at the lamp bead because of the highlighted version. Avoid hurting eyes Note: •When the positive and negative poles are uncertain, please use 19V voltage to detect the positive and negative poles. Do not use 300V voltage to detect the positive and negative poles. 300V voltage may cause damage to the equipment. Short-circuit the pen for three seconds to switch between high and low voltage. Package included: •1 x LED Tester •2 x Test Pen with Line •1 x English User Manual