Abstract: In differential amplifier circuits of the type having first and second transistors, the emitter of each transistor is connected to a different current source and the emitters are coupled by a ceramic filter tuned to 455 KHz. In one embodiment, wherein the transistors have symmetrical resistive loads, an inductor is connected across the filter to tune out capacitance across the terminals of the filter. In another embodiment, the circuit includes an unbalanced and complex load. In yet another embodiment, the circuit has active load circuitry and an inductor is connected across the filter to tune out capacitance across the terminal of the filter.

Abstract: The smoke detector is powered by standard AC current and a stand-by power source consisting of rechargeable batteries. A detector is provided for detecting the loss or failure of AC power, and the shift to the stand-by power source. The power loss detector initiates a time delay after which the smoke detector signal alarm is energized to alert the user about the loss of AC power. If AC power is restored before the time delay interval, the signal is not energized since the user need not be alerted. If the alarm is energized to alert the user of a loss of AC power, a manual reset switch may be used to terminate the alarm. If the manual reset switch is not used, the alarm is terminated automatically upon the restoration of AC power.

Abstract: An FM receiver includes a varactor tuned RF filter to which is applied a bias voltage and a 20 Hz sinusoidal signal for varying the varactor capacitance and the resonant frequency of the filter. As a result, an FM broadcast signal in the pass-band of the filter is phase-modulated by the filter. The second harmonic of the phase modulation is recovered and coupled to a synchronous detector driven at a 40 Hz rate to provide an error voltage. The bias voltage is related to the integral of the error voltage. A difference between the frequency about which the tuned circuit periodically varies and the carrier frequency of the FM signal cause the bias voltage to vary so as to reduce the magnitude of the difference, thereby fine-tuning the receiver.

Abstract: An electronic digital thermometer is provided with temperature-responsive means for producing pulses at a frequency related in a known manner to a sensed temperature. A control means permits the transmission to a counting means for a fixed period of time only of a selected one only of at least two predetermined portions of the pulses. The portions of the pulses transmitted are selected to be proportional to the magnitudes of the sensed temperature as expressed in respective temperature scales, preferably the Celsius and Fahrenheit scales. Decoding and display means are coupled to the counting means for converting the number of pulses counted by the counting means during the fixed period of time into a digital display of the sensed temperature in the selected scale.

Abstract: Equipment having a source of substantial heat is provided with a ventilated housing and an electronic assembly which can be mounted between ventilating air inlet and outlet opening means in the housing. The electronic assembly includes a plurality of parallel spaced-apart plates of which at least one of each adjacent pair of plates has electronic circuitry mounted thereon, the size and configuration of the inlet and outlet opening means and the spacing between the adjacent pairs of plates being sufficient for the flow of adequate ventilating air for the cooling of electronic circuitry mounted on the plates. The electronic assembly may be assembled into an integral unit by means of unique support elements prior to being mounted in the ventilated housing.

Abstract: An electric thermostatically controlled drip coffeemaker has a generally upright C-shaped housing with a lower horizontal leg having a heated carafe support, an upper horizontal leg having a water spreader, and a vertical leg enclosing an accessible water reservoir. An electrically heated hot water generator in the lower leg has an inlet connected to the water reservoir and an outlet connected to the spreader by tubes through a separate definitive condenser located in the vertical leg entirely below the reservoir. The condenser includes an elongated generally cylindrical member larger in cross section than the connecting tubes and having an off-center radially directed water inlet from the hot water generator at the bottom thereof. Shaped and aligned baffle and flow directing means are disposed in the member to impart a non-swirling, vortex preventing, upward flow to the heated water. A captured, limited travel ball check valve disposed in an outlet at the top of the member permits vertical outflow only.

Abstract: An improved power supply cord connection to an electrically heated flatiron having a permanent connected power supply cord extending vertically from the rear of the flatiron handle permits the cord to frictionally swivel or pivot from front to back along the longitudinal axis of the handle in an elongated slot in the handle between a forward non-interference position when the flatiron is in a multi-point heel rest position and a rearward position preventing cord interference with the work during use of the flatiron.The cord includes a bushing enclosing the cord conductors and an integrally formed enlarged head within the handle straddling the slot and locking the bushing therein. Transverse pivot ribs on the sides of the slot cooperate with notched friction bearing ears on the enlarged bushing end to allow the bushing to pivot between limit stops at the front and rear of the slot.

Abstract: An electric drip coffeemaker has a generally upright C-shaped housing with a lower horizontal leg having a heated carafe support, an upper horizontal leg having a water spreader, and a vertical leg enclosing an accessible water reservoir. An electrically heated hot water generator in the lower leg below the carafe support has an inlet connected to the reservoir through a one-way inlet valve and an outlet connected to the spreader by tubes through an interposed separate definitive steam condenser located in the vertical leg entirely below the reservoir. The condenser includes a plenum chamber larger in cross section than the connecting tubes and has a single inlet for water from the hot water generator at its bottom and a single outlet to the spreader at its top. A check valve in the chamber outlet permits only unidirectional water outflow from the condenser to create a "scrubbing" effect cleansing the passages of mineral deposits and preventing clogging.

Abstract: A mechanical force to electrical signal transducer includes a flexible metal body operable as a beam in which a bending strain is to be measured as a measure of a mechanical force. At least a part of one surface of the metal body includes an electrical insulating material with a resistance element formed from a layer of a thick film resistor ink of the type used for thick film integrated circuits fused upon the electrical insulating material. A plurality of such transducers may be combined in a weighing scale, with the individual transducers electrically interconnected to provide for electrical summing of the transducer signals to provide a total weight measurement.

Abstract: In a portable electric appliance that is cord connected to internal electric terminals by multiple conductors as in an iron, an improved strain relief between the cord and appliance comprises a housing chamber at the cord entrance with a cover over the chamber enclosing the conductors. A formed pocket in the chamber has a straight rear wall and a non-parallel sloped wall both molded as part of the housing and spaced from the rear wall, the two walls angling toward the cord entrance. A boss in the pocket is formed on the rear wall extending toward the sloped wall to define a pair of spaced conductor channels and also a central anchor to secure the cover. A separate barbed wedge-shaped member with barbs directed away from the cord entrance fits between the pocket walls to straddle the boss and slide in the channels.

Abstract: A stacked snap-acting thermostat assembly in which a modification is provided of a single structural bracket extending over all the blades and mounted on and above the supported end with an enlarged integral portion having a bore therethrough to form an elongated bearing guide and support a control shaft rotatably in the bore contacting the tension part of the first element to position the upper spring blade.

Abstract: A toaster-oven appliance has a control circuit which enables a user to program the operation of the appliance through a keyboard with audible feedback and which includes functional keys for selecting one mode of operation from available BAKE, BROIL, SLOW COOK, TIMER and TOAST modes, and numerical keys for entering a temperature, time interval and toast color. The BAKE and BROIL functions may be used with the TIMER function to provide TIME-BAKE and TIME-BROIL functions. An interactive digital display is provided to display a user selected function, temperature, time interval, or an error indication in the event that an impermissible entry is made. In the presently preferred embodiment that is described, the control circuit includes microprocessor-based programmable digital logic. The microprocessor operates under the direction of a master program.

Abstract: A piezoelectric element is arranged to receive a mechanical pressure signal and to generate a resultant voltage which is connected to a voltage threshold device for detecting a voltage signal above a predetermined threshold value. The threshold device comprises a two state circuit operable to change state in response to a signal above the voltage threshold. The apparatus is especially adapted to be incorporated within a platform scale for energizing a scale reading indicating system.

Abstract: A rotary cutter blade for use in an unfluted constant diameter bowl of a motor driven food processor with a rotatable hub mounted on a vertically oriented drive shaft where the blade comprises a pair of generally parallel straight razor blade-type cutters secured to and extending oppositely away from the hub and terminating closely adjacent the bowl inner surface. A pair of similarly directed generally parallel straight integral support arms are vertically spaced on and extend oppositely away from the hub. Support arms having an average width greater than the cutters for adequate support.

Abstract: A coffeemaker is provided with a power circuit and a control circuit. The power circuit is connected to a household source of electric power and it is activated by a relay switch. The control circuit includes a relay coil for the switch, and a triac that may be triggered into conduction when a turn on signal from an electronic timer module is applied to the control terminal of the triac simultaneously with the application of direct current control circuit voltage across the triac. Thereafter, the triac remains in its conductive state so long as the direct current flowing through the triac remains above a minimum level. Subsequent removal of the turn on signal from the control terminal of the triac has no effect on the operation of the power circuit which includes the coffeemaker heating means so long as the direct current flowing through the triac remains above a minimum level.

Abstract: A support arrangement for readily mounting the diaphragm of a piezoelectric transducer on a desired node ring, the diaphragm having coaxially mounted thereon a circular piezoelectric element having a diameter substantially the same as that of the node ring. The diaphragm is axially clamped on the node ring between first and second support members. The first support member includes first locking means extending therefrom into engagement with the second support member to axially lock the first and second support members together, and the second support member includes second locking means extending therefrom into locking engagement with the first locking means to lock the first locking means in engagement with the second support member.