Abstract: An arrester includes a switch and a lightning detection breaker connected to the switch. The lightning detection breaker includes a metal conducting terminal electrically connected to an earth return, a DC power supply terminal, a ground terminal and an output terminal. When the power supply is under a lightning strike, a potential difference of both the DC power supply terminal and the ground terminal of the lightning detection breaker will go up to several thousands of volts. However, a voltage of the metal conducting terminal will not go up because the metal conducting terminal is electrically connected to the earth return. The switch will automatically become open circuit by the lightning detection breaker, and therefore an electronic device connected to the arrester is protected from damage done by the lightning.

Abstract: A high-voltage AC LED driver circuit has a rectifier unit, an LED unit, a voltage-controlled transistor, a current detection unit, a control unit and a shunt unit. The shunt unit has a current limiting transistor for limiting a current flowing through the shunt unit to be lower than the working current. The current flowing through the voltage-controlled transistor will be higher than 0 (A) although an AC voltage is boosted. In addition, the voltage-controlled transistor can extend its working voltage and is prevented from being over heated.

Abstract: An LED AC driving circuit capable of adjusting operating voltage has a rectifying unit, an LED unit, a voltage-controlled transistor, a current detecting unit and a current regulating unit to form a power loop. Further, a resistance adjusting unit is connected to the voltage-controlled transistor in parallel. The current regulating unit detects the operating power of the voltage-controlled transistor. When the detected operating power is zero, the resistance of the resistance adjusting unit is increased for increasing the current flowing through the voltage-controlled transistor. When the detected operating power becomes larger than a maximum rated power, the resistance of the resistance adjusting unit is decreased to reduce the current. Thus, the operating power is maintained between zero and the maximum rated power.

Abstract: A flicker-free LED driver circuit with a high power factor has a rectifying unit connected with an AC power source, an LED module connected in series with the rectifying unit, a capacitor module connected in parallel with the LED module, and a constant current circuit connected in series with the LED module and the capacitor module. When the voltage output by the rectifying unit is smaller than a junction voltage of the LED module, the capacitor module discharges to the LED module so that the LED module does not go out, thereby eliminating the flickering. The input impedance of the rectifying unit can be regarded as a capacitive reactance element connected in parallel with a nonlinear resistive element. The internal resistance of the constant current source approaches infinity. Therefore, the power factor of the flicker-free LED driver circuit approximates 1, achieving a high power factor.

Abstract: A continuous dimming AC LED device is operated in association with a dimmer. When the dimmer adjusts brightness, the voltage supplied to the AC LED driver is reduced to decrease the brightness of an LED unit. When the supplied voltage is reduced to a working voltage required by the AC LED driver, a control unit detects the supplied voltage being lower than the working voltage, A control end of a voltage-controlled switch disconnects from the AC LED driver and connects to a power supply. Therefore, even the supply voltage is below the working voltage of the AC LED driver, the LED unit is prevented from being immediately turned off to maintain some brightness. With the dimmer, the brightness of the LED continuously and gradually.