Abstract: A device and a method for controlling the rotation of the turntable of a microwave oven to return to the same position as when the present cooking cycle began. The device includes: an optical turntable rotation sensor unit, which is installed so as to emit an optical signal into a transmission hole, formed in the shaft of the turntable, during cooking and which is to recognize the rotation of the turntable by intermittently receiving the optical signal that passes through the transmission hole; and a microcomputer for controlling the rotation of the turntable after cooking has ended, if necessary, on the basis of the data from the turntable rotation sense unit. The rotation sense unit includes a photodiode and a phototransister. The transmission hole formed in the turntable shaft enables the optical signal emitted from the photodiode to pass through it and reach the phototransister.

Abstract: An oven includes a chamber for locating food for heating. An indicator is provided for signalling the existence of food in the chamber. A sensor may react to the weight of the food on a support in the chamber, or a light beam directed in the chamber and interrupted by a food or receptacle for thereby indicating the existence of food. A time delay may be provided between the sensing of the existence of food and the activation of the indicator. In other situations the indicator system operates in other ovens, autoclaves, and furnaces having workpieces for science, technology, and industry.

Abstract: The weight sensing apparatus of this invention which is made for quick and exacting sensing of a foodstuff's weight to be cooked, includes a pair of arms extending downward from the bottom of a turntable and a pair of projections extending inward from the body of a support member which supports the rotating turntable. When the turntable rotates, the arms engage with the projections so that the support member can rotate at the same speed as that of the turntable. The plurality of guide rollers, which are rotatably connected to the support member, press down at least one or more weight sensors which are disposed in a groove offering a circular track, and thereby sensing the weight of the foodstuff quickly and exactly.

Abstract: A cooking apparatus provided with a weight unit changing key for changing a weight unit and an operation detection means for detecting that the weight unit changing key has been operated plural times, wherein when the operation detection means detects that the weight unit changing key has been operated plural times, the apparatus is placed in a standby state for the weight unit changing operation, and the weight unit can be changed by the subsequent operation so that a user not familiar with the apparatus can easily change the weight unit without a failure.

Abstract: A cooking vessel placed in a desired orientation on a turntable on an oven is automatically returned to that desired orientation at the end of a cooking operation. A sensor on the floor of the cooking chamber senses the movement of support rollers of the turntable to determine the angle by which the turntable must be rotated at the end of the cooking operation to bring the cooking vessel back to the desired orientation.

Abstract: A microwave oven is provided with a weighing device comprising a plate having a vertically movable shaft, and a fluid-containing bladder or a fluid-containing piston and cylinder assembly, and a pressure sensor for sensing the weight of a food product to be cooked in the oven. The problem residing in that the electronic components included in prior-art weighing devices are placed in an unsuitable environment under the cavity bottom of the oven is solved by placing the electronic components on a circuit board for the remaining control electronics in a space separate from the space under the cavity bottom. This solution means that the vertically movable shaft generates a pressure change in the bladder or the piston and cylinder assembly. This pressure change is transmitted to the pressure sensor, which generates a weight-indicating signal.

Abstract: A method and apparatus for detecting the presence of a saucepan on the hob plate of a glass ceramic cooking hob associated with a heating element includes measuring the variation in a physical characteristic of an electrical resistive element positioned between the heating element and the hob plate of the glass ceramic cooking hob caused by a body or saucepan being placed on the hob, the variation being evaluated by control means which, on the basis thereof, controls the heating element to change its operating parameters.

Abstract: A food weight sensing device of a microwave oven using a variable capacitor of which the capacitance is varied in accordance with pressure applied thereto. The device comprises of first and second electrodes placed on a side portion of a lower surface of a cooking chamber, the side portion being included in a rotating trail of a roller applied with part of the food weight, each of the electrodes comprising a metal plate spring. A spacer is interposed between the first and second electrodes to space out the electrodes from each other at a predetermined interval. A rubber plate engages with the first electrode for transmitting the food weight to the first electrode. The first electrode comprises a center circular push part, an outer flange part and at least two arcuate ribs connecting the center circular push part to the outer flange part. The spacer is made of a metal so as to electrically connect the first electrode to a printed circuit board.

Abstract: A toasting machine comprising heating elements, an on/off switch for initiating a toasting cycle, a toast colour selection knob for setting a selected time period for a toasting cycle, a timing circuit arranged to measure the elapsed time since a previous toasting cycle and including time booster means, a control circuit responsive to the toast colour selection setting and the timing circuit, a connection line and plug for connecting the toasting machine to an electrical power supply so as to supply power to the heating elements on initiation of a toast cycle by the on/off switch and under control of the control circuit, a temperature measuring device arranged to measure the temperature of the toasting machine and supply a temperature representing signal to the control circuit, the control circuit being arranged to control the timing of a current toasting cycle in dependence both on the setting of the toast colour selection switch and on the timing circuit, so that the toasting cycle time period during which

Abstract: Cooking apparatus (1) including a cooking chamber (2) comprising an electric resistance browning device (3) for the foodstuff disposed in the chamber (2) and a device (4) for the generation of microwave energy disposed outside the cooking chamber (2) and adapted to supply the chamber with microwave energy. An electric supply circuit supplies the browning device (3) and/or the device (4) for generation of microwave energy. A selector permits triggering a heating sequence to be performed on a foodstuff. This sequence causing the browning device and/or the device for the generation of microwave energy to kick in. The selector recognizes the nature and weight of the foodstuff, and a control actuates the electrical supply circuit as a function of information from the selector. The control comprises a storage memory receiving the information from the selector, and a microprocessor supplying signals applied to the supply circuit as a function of the information contained in the storage memory.

Abstract: A cooking apparatus for heating food to be served and capable of being operated with utmost simplicity without using and choosing various cooking-mode selection keys so as to achieve superb ease-of-operation. The cooking apparatus includes a cooking chamber for placing and storing food to be heated by the apparatus and a detector for detecting a state of a door attached to the cooking chamber, the door being freely openable and closable against an opening portion of the cooking chamber. An optical sensor, having a plurality of light emitting portions is disposed in a side of the cooking chamber and a plurality of light receiving portions are disposed counter to the light emitting portions. A drive unit is provided for driving the optical sensor and a judgement unit verifies and determines a cooking mode suitable for the food placed in the cooking chamber responsive to a signal from the optical sensor, where the drive unit is activated when the detector detects that the door is closed.

Abstract: A microwave oven has a photosensor to detect an objected in a cooking compartment. The photosensor, including a light emitter and a light receiver, detects whether a turntable is absent or present in the cooking compartment. The light emitter projects a plurality of pulses of light in sequence. A controller counts the number of pulses of light detected by the light receiver and controls the oven based on the number of pulses of light detected as compared to the number of pulses of light emitted.

Abstract: A food weight detecting device for a microwave oven which can detect food weight exactly according to the speed variation of the rotating roller rolling on a base plate having a protrusion formed thereon with predetermined ascending and descending angles. According to the device, the possibility of incorrect weight detection due to such defects as corrosion or secular change of a parallel plate capacitor in the conventional capacitance- detection type device can be eliminated. Thus, reliability of automatic heating control is increased and an inexpensive motor which needs not be heat-resistant can be employed.

Abstract: A cooking oven is provided with a weight detection unit for detecting the weight of a cooking object placed on a turntable. The turntable is movable into and out of a heating chamber associated with the cooking oven by means of a moving unit drivingly connected to the turntable through a lever and connecting rod. A heater and a rotary drive unit for rotating a table upon which the turntable is mounted are controlled according to a signal from the weight detection unit. The cooking oven is also provided with an external input unit for supplying data on the heating operation and on the driving of the turntable. Either manual or automatic operation of moving the turntable back and forth can be selected according to a signal from the external input unit.

Abstract: An electric thermos bottle capable of automatic water release/cutoff which has an automatic water release/cutoff power switch turned on by the weight of a cup placed thereon. When the power switch is on, it actuates an electric air pump inside the top head of the thermos bottle to produce compressed air which passes an air communicating pipe and enters the sealed thermos bottle. At this point, the air pressure in the thermos bottle suddenly increases and therefore, forces water reserved in the thermos bottle to automaticaly release from a blow off pipe before flowing into the cup below a water exit. When water in the cup reaches a predetermined level, the water completes an override circuit which includes conductive elements in the cup and the metal interior of the thermos, in order to disconnect the air pump and automatically discontinue the release of water.

Abstract: A device and method for regulating a cooking apparatus. In order to obtain an effective servocontrol of the desired temperature with a cooking surface, when cooking for example by induction, a servocontrol curve is used in the plane (i.e., temperature, variation of the temperature as a function of time). Each time the curve is crossed the heating power is cut off or reduced. The device and method applies principally to monitoring of the heating device. The device according to the present invention is particularly well adapted to cooking surfaces and especially to cooking surfaces wherein cooking is done by induction.

Abstract: An electric toaster that enables power to be disconnected from the heating elements upon completion of a toasting cycle regardless of the position of the main product supporting the carriage in the toasting compartment. The toaster has an electromagnetic latch and an auxiliary member carried by the main carriage which is movable relative to the main carriage. The auxiliary member is urged by biasing member to move in a direction away from the electromagnetic latch but able to be held thereby when the latch is activated. The auxiliary member also is arranged to close main power supply contacts to supply power to the heating elements when the auxiliary member is held by the latch, but to open said main supply contacts when the auxiliary member moves away from the latching means under action of the biasing member. The toaster may also include a sensor to sense abnormal conditions in the toaster to disconnect power from the heating elements when such abnormal conditions occur.

Abstract: A high frequency heating device designed to swiftly and accurately detect a to-be-cooked food placed on a turn table within a cooking chamber to thereby set up a cooking time or a driving time of a magnetron in accordance with a weight of the food, so that an appropriate cooking can be performed. A weight sensor on a lower bottom surface of the cooking chamber in order to detect the weight of the to-be-cooked food located on a turntable during a rotation of the turntable.

Abstract: The device comprises a sensor supplying a sensor signal which varies as a result of the placement of a cooking vessel in a heating zone of a heating appliance. The device includes evaluating circuit which, as a function of the sensor signal, supplies an output signal. The evaluating circuit produces the output signal as a function of the rate of change of the sensor signal to indicate the presence or absence of cookware in the heating zone of the heating appliance.

Abstract: Electric hotplate (1) comprising a temperature sensor (3) which includes a temperature-sensitive surface (4) projecting with respect to the surface of the hotplate intended to receive a cooking receptacle. The sensor (3) comprises in combination a device (5) for measuring the temperature of the temperature-sensitive surface (4); a detector (7, 8) for detecting the presence of the receptacle on said hotplate; and a fuse (6, 23) comprising a thermal safety element in contact with the temperature-sensitive surface (4) for cutting off the electrical supply to the hotplate (1) when the temperature reaches a predetermined maximum value.

Abstract: When a carriage of the toaster is in a lower position, a switch (21) is closed and power passes through a bridge rectifier circuit (22) to an integrated circuit (19), which, for the normal cooking operation, switches SCR (20) off so that a relay (7) is energised, switching switches (8) and (9) on to energise heating elements (2) and (3). Power is also supplied to a latch (27) to hold the carriage in the lower position. If, however, a fault detection is input from a residual core balance (12) to the integrated circuit (19), SCR (20) is switched on so that power from bridge rectifier (22) is shorted. This causes relay (7) and latch (27) to be de-energised so that the heating elements (2) and (3) are turned off and the carriage is returned to the upper position, causing switch (21) to open.

Abstract: A food service rethermalization process including a tray having first and second receiving hot dish receiving areas, at least one cold dish receiving area and an end wing area for holding eating utensils, napkins and the like. First and second selector or actuator knobs are mounted in the tray adjacent to the first and second hot dish receiving areas, respectively, and can be separately turned to on or off positions. When the tray is inserted in a rethermalization cart and the first and second heating pods of the cart are at the first and second areas respectively, the heating pods whose associated knobs are in the "on" position are switched on and the food at the associated areas thereby heated in a programmed manner. After the knobs have been turned as needed and before the tray is inserted in the cart, an over-all insulated cover is secured to and on top of the tray. The cover thermally separates and covers the different areas including the wing area.

Abstract: A control circuit for a binding apparatus using a binder covers having resistance heating strips in a heat activated adhesive includes a power control to output a constant power to the heating strip. A duty cycle of the power signal supplied to the heating strip is controlled dependent upon the resistance of the strip. Fault detection circuitry indicates an open circuit in the resistance strip and interrupts the power supply. A stress test is performed by a high voltage generator which emits a high voltage pulse at the start of the binding cycle to stress the connections in the binder cover and thereby cause failure of any weak connections before the binding cycle is underway. A timer circuit is also disclosed.

Abstract: A cook-top (10) is provided which includes at least one cooking section (12a) heated by at least one heating element which is activated by function controls (9). It includes at least one detector (20) which detects the presence of a cooking utensil on at least one cooking section (12a), the detector actuating a timing means (22) (24) in order to turn off or to reduce the heating of the cooking section when the utensil has been removed, and to turn on the heating of the cooking section when the utensil is put back on the cooking surface if the absence time has been shorter than a given time.The detector may be responsive (20) (26) to the weight of the utensil and/or the temperature of the heating surface.

Abstract: The rim of an electric radiant heater is formed by a multilayer body (13). It can have the cross-sectional shape of a U, whose interior is filled with a good insulating material. In the interior (23) is placed a sensor coil (23) for a pot detection system, where it is well shielded against heat and mechanical influences.

Abstract: A cook-top (10) includes a plurality of heating elements (11a, 12a) which are activated by function controls. The heating elements are covered by a plate (15) which are fixedly connected to strain-guage modules (30) which detect the forces exerted on the plate as a result of loads placed on the heating elements. By computing the center of gravity of the forces, controls (70, 75, 76) identify a heating element whose load has varied and influence its electric power supply. The power supply may then be turned off, reduced or controlled. The function controls may be pressure-sensitive touch controls.

Abstract: A parameter control system for an oven which may, for example, be a baking oven or a convection oven having the capability of injecting steam into the cooking cavity. The parameter control system precisely controls cooking temperature, cooking time, humidity and air flow in the oven. The parameters can be easily and repeatably set.

Abstract: A "pop-up" toaster is controlled by a microcomputer to operate in a toast, bakery or pastry mode to toast a product to some preselected color. The microcomputer includes a memory for storing indications of the toast color selected for the present toaster cycle (TCOLOR), the toast color selected for the previous toasting cycle (TLAST), the mode selected for the present toasting cycle (MODE) and the previous toasting cycle (LMODE) as well as tables of toaster cycle times and tables of compensation values. The microcomputer counts the number of toaster cycles occurring within a predetermined time of the start of the present cycle (TCYCLE) and also develops an indication (TINT) representing the elapsed time between the end of the previous cycle and the beginning of the present cycle. A toast cycle time is selected from the tables depending upon TCYCLE, TINT and TCOLOR.

Abstract: A control arrangement for an electric food heating device having heating elements for heating foodstuff and providing a source of light impinging on the foodstuff, the control arrangement comprising: a peaking circuit (42, 30) to determine maximum reflected light from the foodstuff and provide a first signal (VI), and measuring subsequently reflected light from the foodstuff and providing a second signal (V2), said peacking circuit including amplifier means (30) for determining the difference between the first and the second signals, and providing a third signal (V3); and a comparator means (26) for comparing the third signal (V3) and a preset signal (VB), the preset signal being proportionate to a desired heating level, the comparator means providing a terminating signal (DONE) to deactivate heating when the preset and the third signals are substantially equal.

Abstract: A cooking appliance is disclosed which has a cooking control system responsive to selection of a given food to be cooked, for indicating the optimum cooking position of the food in the appliance. The appliance may be an oven, with the indicator indicating the optimum position of a shelf in the oven, or the optimum position of the food on the shelf.In a further disclosed feature, a cooking appliance may have an air circulation system, such as a blower, for circulating air about food to be cooked. A cooking control system is responsive to selection of a given food to be cooked for controlling the air flow about the food for optimum cooking thereof.In another disclosed feature, a cooking appliance which has a control system responsive to the selection of given food and the number of rack positions required, will control the rate of energy released from the oven heat sources for optimum cooking.

Abstract: A system is disclosed for curing epoxy in a fiber optic connector. An oven has a receptacle for receiving the connector with an exposed length of an optical fiber projecting therefrom. A heat conductive sheath is positionable on the connector about the optical fiber for distributing heat from the oven and for protecting the fiber when the connector is inserted into the receptacle. Sensing elements are located in the path of insertion movement of the fiber optic connector and conductive sheath to be actuated thereby in response to the connector being inserted into the receptacle. A micro-controller is coupled between the sensing elements and audible/visual signals. The micro-controller includes a timer to actuate the audible/visual signals after a predetermined period of time within which the heater is energized.

Abstract: Apparatus for warming coffee or other beverage includes a warmer plate on which a vessel holding the beverage to be warmed is set, a heater for heating the warmer plate, circuitry for controlling the time the warmer plate is in a heating condition and a weight sensitive switch for enabling the circuitry only when a vessel of pre-determined weight is on the warmer plate. The circuitry further includes components for reinitializing the time the warmer plate is in a heating condition after a vessel is removed from the warmer plate under predetermined time conditions and then replaced thereon.

Abstract: An arrangement of components for constructing a heating device employing super thin conductive film (STCF) heating element includes the STCF heating element, in a layer, attached externally to a pan bottom by means of calcination through an aluminum monoxide film and a base device having terminal units for applying a suitable voltage to the STCF heating element when supporting the pan thereon.

Abstract: A cooking unit includes a heater located below a hot plate and a temperature sensor, which detects the temperature of the cooking unit. A temperature control device has a switching contact which is operated by the temperature sensor and also manually to provide a sensor controlled temperature limitation cut out for at least a part of the heater.

Abstract: A protection device for a waterbed protects the water bladder and water heater from damage due to overheating when a dangerous condition, such as an insufficient level of water within the bladder or an element of the waterbed surroundings interposed between the bladder and the water heater, arises. The protection device employs a detector in the form of two capacitance plates placed adjacent to the water bladder and connected to a circuit which is operative to prevent power from being supplied to the water heater upon detection of a dangerous condition. The capacitance of the detector plates varies with the level of the water within the bladder and with the presence of a surrounding element between the bladder and heater.

Abstract: There is disclosed herein an automatic heating appliance for controlling heating of an object in response to operation of instruction keys and on the basis of the weight of an object to be heated. The appliance includes therein a heating chamber for housing the object, a heater provided on or in the heating chamber for heating the object placed therein, and a turntable provided in the heating chamber for keeping thereon the object during heating. Also included in the appliance are a weight detector for obtaining first weight data in response to the object being placed on the turntable and a temperature compensator for obtaining a second weight data in response to the object being placed thereon, the temperature compensator substantially having the same temperature characteristic as the weight detector.

Abstract: An improved lamp control process and assembly are provided to automatically and efficiently heat objects, such as plates of hot cooked food upon a counter in a restaurant. The lamp control assembly preferably includes heating lamps or heating elements, a photoelectric sensor or other sensor, a power control circuit, and a time delay circuit to slowly turn off the lamps when the plates of food are removed from the counter. Other loads can be controlled similarly.

Abstract: Disclosed is an electric apparatus comprising a housing with a door, a turntable arranged in the housing for rotating an object, a synchronous motor for driving the turntable, and a control portion for controllling the driving of the synchronous motor, the control portion having apparatus for storing the time required for the turntable to rotate once, apparatus for determining whether or not a time period which is approximately a natural number multiple of the time required for the turntable to rotate once, has elapsed since initiation of turntable rotation, and apparatus for stopping an operation for the rotation of the turntable on the basis of the determination that time, which is approximately a natural number multiple of the time required for one rotation of the turntable, has elapsed.

Abstract: A safety mechanism for disabling a portable room heater. A lever which extends from the heating face of the heater is coupled with a shut-off switch. Movement of the lever resulting from draping of an object over the heater opens the switch and shuts off the heater. A buzzer may be wired in parallel with the switch to provide an audible alarm when the switch opens.

Abstract: A heat cooking apparatus accurately detects minor weight variations of an article of food by detecting the weight of the article of food received on a turntable in synchronization with the position of the turntable or its rotational cycle, so as to control the cooking based on such weight variations.

Abstract: A heating apparatus including a heating member for heating a subject, a temperature detector for detecting a temperature of the subject an energizing control element that is electrically connected to the temperature detector so that current conduction to the heating member at a the time when the temperature detector is actuated to operate after the subject to be heated and a switch element for disconnecting the temperature detector to the energizing control element in response to the actuation of the energizing control element. The heating apparatus is appropriate for use in a vacuum coffee maker.

Abstract: A microwave oven turntable having a load-responsive mechanism for self-activating the turntable upon the placement of foodstuff thereon. The turntable includes a base assembly having a planar bottom and upwardly extending sides to form a base interior in which a drive shaft is rotatably driven by a coil spring. A tabletop is coupled to the drive shaft for rotation therewith, but the rate of rotation is determined by the cyclical motion of a governor. The load-responsive mechanism includes a resilient brake member which is aligned in a governor-locking position. The tabletop is linked to the brake member by an actuator and the brake member is sufficient rigid to maintain the actuator and tabletop in a slightly uplifted condition when in the governor-locking position. The placement of foodstuff on the tabletop, however, provides a gravitational force which displaces the brake member into a governor-releasing position in spaced apart relation to the governor.

Abstract: A heating apparatus is provided with the gas sensor for detecting gas or steam generated from an object to be heated and a weight sensor for detecting the weight of the object to be heated. The signal level of the gas sensor indicates whether the change in the amount of the gas or the steam in the exhaust guide portion is a predetermined value of gas or steam generated from the object, to determine the kind and condition of the object to be heated. Also, change in the signal level of the gas sensor is compared to the predetermined value at a detection time period which is based on the weight of the food detected by the weight sensor, to decide whether to continue or stop heating.

Abstract: A semiconductor wafer processing furnace includes an elongated processing chamber enclosing a first zone and a second zone extending along a first reference axis, and a wafer support assembly having a support member and associated translation elements for selectively translating the support member between the zones, along the first reference axis, in response to an applied position signal. Temperature elements control the first and second zones to have selected first and second temperatures, respectively. A controller applies the position signal to the translation elements, in response to an applied control signal representative of a desired temperature of the region surrounding the support member. Responsive to the position signal, the translation elements position the support member along the reference axis such that the temperature of the region surrounding the support member substantially matches the desired temperature.

Abstract: A heating apparatus for use in binding, which apparatus includes a base and a cover member hingedly connected to each other. The cover member includes a binding-receiving compartment positioned above a portion of the base. A pair of spaced electrical contacts are positioned in the base below the binder-receiving compartment for receiving and connecting to the binder-receiving contact. The base includes an electric circuit compartment for housing an electric circuit adapted to apply a current to said conductors upon contact with the book for a predetermined length of time.

Abstract: A heating appliance for heating an object within a heating chamber. In the heating chamber are formed rack rails on which a table is located and a heater. The rack rails are stepwise arranged so as to allow the table to take a desired position corresponding to the kind of an object to be heated. The heating applicance includes a distance-measuring sensor for measuring a distance to the table means or the object. A control unit, may comprising a known microcomputer, controls the heater on the basis of the distance measured by the sensor so as to appropriately heat the object in accordance with its kind.

Abstract: A heating appliance comprising a heating chamber, a heating device for heating an object which is encased in the heating chamber and a turntable provided in the heating chamber and arranged to be rotatable about its own axis and to hold thereon the object. Included therein are an ultrasonic sensor for transmitting an ultrasonic wave toward the object and receiving an echo wave returning therefrom and a control unit for controlling the ultrasonic sensor. The control unit successively calculates the distances of the object from the ultrasonic sensor on the basis of the transmission and reception of the ultrasonic wave and determines the heating condition of the object on the basis of the successively calculated distances and controlling the heater in accordance with the determined distinctive feature. This does not require an input operation in terms of the class and category of the object to be heated, resulting in improving the automation of the heating appliance.

Abstract: In an automatic cooking of cake, a gas sensor and a weight sensor are used to determine a total heating time. The initial weight of a food item (cake) is measured by the weight sensor, and a time (T.sub.W) proportional to a detected value of the weight sensor is determined. The amount (.DELTA.H) of change in humidity level until an arbitrarily chosen timing is detected by the gas sensor, and a time (T.sub.(.DELTA.H)) proportional to a detected value of the gas sensor is determined. These times (T.sub.W) and (T.sub.(.DELTA.H)) are added together to determine a total cooking time. With this arrangement, regardless of the kind and amount of cake and the shape of a vessel, the automatic cooking capable of giving a fine finish can be accomplished merely by selecting a single auto-key called a cake key.

Abstract: A vessel for maintaining a heated liquid hot, includes a receptacle to house the heated liquid, having an electrical heating element integral therewith and power connection leads electrically connected to the heating element; the vessel may suitably include a cup and support plate suitable for coffee and similar hot beverages.

Abstract: An aroma generating apparatus includes a driver circuit which functions as a real time lapse counter and includes a signal indicator to designate the replacement period of useful lifetime of the aroma producing cartridge. The driver circuit continuously operates between a low frequency during the off state of the resistance heating element and a high frequency during energizing of the resistance heating element. The dual frequency permits monitoring ofthe real time operation of the apparatus without the need of providing memory devices to accommodate inoperative periods of the apparatus.