Abstract: A filter includes a circuit board, a low-pass filter circuit, and a high-pass filter circuit. The circuit board includes at least one metal layer, and a dielectric layer attached on the at least one metal layer. The low-pass filter circuit is defined in the metal layer, and includes a main line that has two parallel portions, and a modulating circuit serving as a capacitor connected to the main line of the low-pass filter circuit. The high-pass filter circuit defined in the metal layer includes a main line that has two parallel portions and is connected to the low-pass filter circuit, and a modulating circuit serving as a conductor connected to the main line of the high-pass filter circuit.

Abstract: A power-on reset circuit, connected to an external direct current (DC) power source, to receive DC power signals and generate a reset signal, includes a delay circuit, a combination circuit and a shaping circuit. The delay circuit comprises a plurality of delay units, to delay the received DC power signals and output a plurality of delayed DC power signals. The combination circuit is connected to the delay circuit, to combine the delayed DC power signals into a combination signal, and output the combination signal. The shaping circuit is connected to and turns the combination circuit on and off according to the combination signal and outputs the reset signal.

Abstract: A filter includes a circuit board, a low-pass filter circuit, and a high-pass filter circuit. The circuit board includes at least one metal layer, and a dielectric layer attached on the at least one metal layer. The low-pass filter circuit is defined in the metal layer, and includes a main line that has two parallel portions, and a modulating circuit serving as a capacitor connected to the main line of the low-pass filter circuit. The high-pass filter circuit defined in the metal layer includes a main line that has two parallel portions and is connected to the low-pass filter circuit, and a modulating circuit serving as a conductor connected to the main line of the high-pass filter circuit.

Abstract: A power-on reset circuit, connected to an external direct current (DC) power source, to receive DC power signals and generate a reset signal, includes a delay circuit, a combination circuit and a shaping circuit. The delay circuit comprises a plurality of delay units, to delay the received DC power signals and output a plurality of delayed DC power signals. The combination circuit is connected to the delay circuit, to combine the delayed DC power signals into a combination signal, and output the combination signal. The shaping circuit is connected to and turns the combination circuit on and off according to the combination signal and outputs the reset signal.