Product Parameters：†Vin: AC 85-265V†Vout: DC 0-330V (Automatic + Adjustable)†Voltmeter Accuracy: < (± 0.5 ± 1%Vout) V†Iout: 0-150mA (Automatic + Adjustable)†Constant Current Board Testing Current: 0-999mA†Ammeter Accuracy: <(±2 ±1%Iout) mA†Pinput: 50VA (MAX)†Temperature: -20℃~+40℃Testing Methods：Default factory setting: Output Voltage 330V, Output Current 30mA. You can testing the backlight of TV with any size at this default settings.1. Self-testing: Plug in, turn the power switch on. The voltage is around 330V, current is 0; Contact the probes together, voltage changes to 0 and current changes to around 50mA, then testing can be started.2. In testing: Voltage = ‘0â€, SHORT CIRCUIT. Voltage = ‘330Vâ€, OPEN CIRCUIT.3. Testing single LED bead (Set voltage around to 20V and the current switch to 1mA): A. With right polarity: the voltage shows on the tester of a normal LED bead is about 80% of the rated voltage, for example, the operating voltage of the LED bead is 2.4V if its rated voltage is 3V; B. With wrong polarity: Voltage display the open circuit voltage.4. Testing LED strips: Set the voltage to around 200V, change the current if need adjust brightness.Package Including1*LED tester1*The power plug1*Cloth bag1*instructions1*Test Probe