A circuit for switching the power supply between the FM and AM sections of an AM-FM radio receiver. A single-pole single-throw switch is used in conjunction with a transistor circuit to provide the required single-pole double-throw switching function.

An electronic oven comprising an oven-defining structure equipped with means for effecting the browning action on an object to be heated, said browning means including means for creating a forced circulation of air and a heating assembly, whereby hot air of relatively high temperature can advantageously be directed toward the object so that the browning or scorching action can be performed in a short time as rapidly as the object can be heated solely by the application of high frequency energy.

A socket for electronic components particularly useful for "dual-in-line" packages, comprising a housing of electrical insulating material having an end wall defining a closed end, an opposite open end, and a plurality of electrical contact members extending generally between these ends, each having a spring portion providing a contact surface, each contact surface engaging the outer surface of one of the leads of the electronic component at a point along the length of the lead, when the compone...

An all-electronic keyboard avoiding mechanical motion of keys, and particularly suitable for digital computer input is described. The keyboard has a matrix of keys located at intersections of columns and rows and electronic oscillations are established in circuits including keys of the keyboard. When an individual key is contacted manually, the change in capacitance detunes the oscillating circuit in the column and row in which the selected key lies. Electronic sensors and decoders note the colu...

An electronic thermometer having a casing, a probe removably mounted in a probe well in the casing, a thermistor mounted in the top of the probe, a resistance bridge with the thermistor connected as one of the bridge resistances so that the bridge output indicates the temperature of the thermistor, a meter responsive to the bridge output for displaying the temperature of the thermistor, and at least one, and preferably two wells in the casing for each holding a plurality of disposable probe cove...

An electronic spirometer having an accurate indication of exhaled tidal or minute volume. In the preferred embodiment, an adapter fits on the exhalation port of the breathing circle and monitors a patient's exhaled volume when being ventilated. A heated thermistor mounted in the adapter senses the gas flow as an approximate fourth power function of the current necessary to maintain the thermistor at a constant temperature. A signal conditioner provides the current required to keep the thermistor...

A pulse adder, producing an output representing the sum of the amplitudes of a sequence of electric pulses, has a storage capacitor charged by each pulse and stabilizing means opposing any reduction of voltage across the storage capacitor. Apparatus is also disclosed for producing a signal representing the average value of continuously-variable voltage over a period, comprising switching means for chopping said voltage into pulses, two pulse adders receiving said pulses, one adder for pulses of ...

A circuit including an amplifier and a transistor for rectification including a feedback path to maintain the output voltage proportional to the input voltage. The amplifier also may include a feedback resistor to maintain the transistor at cut-off in the absence of an AC input signal.

Electronic apparatus for measuring temperatures by means of a thermistor in one arm of a Wheatstone bridge, bridge balance being accomplished by a plurality of shunt resistances selectively inserted into the balancing arm of the bridge by counter controlled switching, the counter state being altered by gated clock pulses to provide a digital indication of measured temperature. Anticipation circuitry is provided for correlating the time between counter clock pulses with the time vs. temperature c...

Disclosed is an electronic wristwatch in which a crystal oscillator drives an electromechanical resonator tuned to the oscillator output. The high frequency oscillator is connected through an integrated circuit divider and driver to the resonator coil so that the coil oscillations are slaved to the frequency of the divider output. A lever, rotatable on an eccentric forming a part of the resonator staff, drives an index wheel, in turn connected through a gear train to the watch hands. Provision i...