Abstract: In a microcomputer controlled apparatus there is provided a device for memorizing that the battery voltage has dropped below a predetermined value and a control device for stopping the execution of the program. Subsequently if the battery voltage rises and execution of the program is restarted, the control device determines from the memorizing device that a voltage drop occurred and forcedly stops the execution of the program until the old discharged battery is replaced with a new fully charged battery.

Abstract: An air humidifier includes a water level detector that detects the water level in the water reservoir, and first and second light-emitting elements. The first and second light-emitting elements are selectively energized to emit light in response to whether the water level detected by the water level detector is at or above or below a predetermined level so as to permit quick visual inspection of the relative water level in the reservoir.

Abstract: A humidifier for controlling ambient moisture includes a moisture sensor having a capacitor component and a resistor component which may vary in response to the ambient moisture, a pseudo AC square-wave generator for supplying a square-wave source voltage to the sensor which is the sum of two separate square-wave voltages, and a moisture detector section to which a sensor output voltage and a reference voltage electrically representing an objective moisture value are supplied. When the sensor output voltage reaches the stable potential after the transient phenomenon to be caused by the sensor capacitor component, the moisture detector section compares the stable voltage with the above reference voltage, thereby performing the moisture detection which faithfully corresponds to the sensor resistor component.