CHARACTERISTIC SWITCHING CIRCUIT

摘要

The capacitor (5) has one terminal earthed and the other connected to the switching contact of a switch device (25). An additional switching device (29) is connected between the common contact of the first switch device (25) and earth through a fixed capacitor (28). The arrangement is said to avoid the formation of parasitic capacitances, when the circuit is integrated. Alternatively, the time constant can be varied widely by the provision of a large capacitor external to the integrated circuit. A switching capacitor is added for switching the characteristics of time-constant circuit combined with a fixed capacitor. The time constant-determining circuit has a low-pass filter which is switched by a combination of switched capacitors and capacitances.