Abstract: An airbag control circuit comprises a transformer having a primary coil connected to a first sub-circuit and a secondary coil connected to a second sub-circuit, an ignition impedance for initiating deployment of the airbag, a first energy storage device connected to the secondary coil of the transformer, wherein the first sub-circuit transmits a first signal to the second sub-circuit via the transformer, and wherein the first signal charges the first energy storage device, a first sender/receiver unit connected to the secondary coil of the transformer and receiving the first signal, and a frequency analyzer connected to the first sender/receiver unit, wherein the frequency analyzer connects the first energy storage device to the ignition impedance in response to a predetermined change in a frequency of the first signal.

Abstract: According to the present invention, there are provided an input terminal, an output terminal, an a.c. generating circuit and a voltage-anomaly detecting circuit. Power supplied to the input terminal is outputted from the output terminal based on an output produced from the voltage-anomaly detecting circuit. When the voltage of the supplied power is abnormal, a.c. power produced from the a.c. generating circuit is outputted from the output terminal. Further, a boosting circuit, a rectifying circuit and a capacitor are provided. The a.c. generating circuit is constructed so as to produce a.c. power from a charged voltage of capacitor. Owing to this construction, a power supply apparatus having a function for compensating for changes in voltage can be provided which is small in size and is inexpensive.

Abstract: A wiper control device includes a wiper switch having a variable resistor which is switched to the respective resistance value corresponding to the respective operation mode of the wiper apparatus. An interface circuit is provided with a reference resistor and a capacitor. A microcomputer is provided with a reference charging port for changing the capacitor through the reference resistor, a detective charging port for changing the same capacitor through the variable resistor switched into various resistance values corresponding to the respective operation modes and a reading port for reading as to whether the capacitor is changed up to a predetermined potential level. The microcomputer determines the selected operation mode on the basis of a relative value calculated from the time required for charging the capacitor through the reference resistor by the reference charging port and the time required for charging the capacitor through the variable resistor of the wiper switch by the detective charging port.