Abstract: A semiconductor switch circuit of field-drive type includes a bipolar component having forward blocking and reverse blocking junctions, and p-channel and n-channel IGPETS connected across the bipolar component so as to short-circuit its forward blocking junction. The switch circuit operates to turn on or off in response to the voltage signal to the gate circuit which is isolated from the bipolar component, irrespective of the polarity of a voltage applied across the bipolar component.

Abstract: A full wave rectifier comprises an input terminal supplied with an AC signal and an output terminal for delivering a rectified DC signal. An operational amplifier having an inverting input terminal, amplifies the AC signal. A rectifier gain setting is provided by a first resistor connected between the input terminal and the inverting terminal of the amplifier. A second resistor, having the same resistance as the first resistor, is connected between the inverting terminal and output terminal of the amplifier. A depletion type MOS FET operates responsive to the output of the amplifier, for performing a switching operation.

Abstract: In a switched capacitor filter of a first-order responsive to a filter input signal for producing a filter output signal by carrying out sampling operation at a predetermined sampling rate by the use of switching circuit, a capacitor, and an integrating circuit, a voltage divider produces a voltage divided signal in response to the filter input signal to reduce a total capacitance determined by capacitances of the capacitor and the integrating circuit. The voltage divided signal is sampled by the switching circuit to be sent to the integrating circuit at the sampling rate through the capacitor. The integrating circuit produces the filter output signal as a result of integration. In addition, an additional switched capacitor filter of a first-order is connected in cascade to the filter to form a switched capacitor filter of a second-order.