Abstract: Electrothermal conversion elements, apparatus and methods for use in comparing, calibrating and measuring electrical signals utilizing a thin film heater on a thin, low mass, low thermal conductivity substrate and low mass thermoresistive or PN junction thermal radiation sensors. The element emits IR radiation in response to electrical input. The radiation is collected and converted to an electrical signal proportional to the RMS value of the input signal. Isothermal operation enhances both IR and electrical operation.

Abstract: Electrothermal conversion elements, apparatus and methods for use in comparing, calibrating and measuring electrical signals. The element emits IR radiation in response to electrical input. The radiation is collected and converted to an electrical signal proportional to the RMS value of the input signal. Isothermal operation enhances both IR and electrical operation.

Abstract: A method and apparatus for the comparision of AC signals by electrothermal means in which both signals are applied to an electrothermal converter, such as a thermocouple converter or a thermoresistive converter, and the temperature produced by the signals is converted to a difference signal. The DC component of the difference signal is used to maintain the electrothermal converter at a stable operating temperature. The AC component of the difference signal is used to indicate the difference between two signals when used as a comparator, to control the amplitude of a reference standard's output when used as a voltmeter or calibration standard, and also to control the amplitude of an oscillator when used as a calibration standard.

Abstract: A thermal transfer device for use in the measurement of alternating current comprising an evacuated enclosure containing a first electrical conductor heated by the alternating current being measured and a thermal sensor to provide an electrical signal representative of the temperature of the conductor, wherein the first electrical conductor is formed of a low temperature coefficient of resistivity material, and the thermal sensor is a second electrical conductor of a relatively high temperature coefficient of resistivity material thermally coupled with and encompassing most of the first electrical conductor.

Abstract: A compensation circuit for a heater wire and a temperature sensor, the temperature sensor generating a signal whose amplitude is dependent upon the amplitude of the voltage across the heater wire. The circuit comprises a comparator circuit and a priority encoder circuit for generating digital information that is a function of the amplitude of the voltage in the heater wire; a multiplexor/demultiplexor circuit, responsive to the digital information generated, for generating a reversal error compensation signal, the generated reversal error compensation signal having an amplitude that is a function of the Peltier and Thomson effects associated with the heater wire; and amplifier/chopper circuits adapted to generate a compensated sensor signal that is a function of the reversal error compensation signal and the uncompensated sensor signal.

Abstract: The present invention comprises a plastic case for housing electronic instruments and the like, having a top and bottom panel with two side panels connecting them. The edges of the top and bottom panels are mounted for telescoping movement in the side panels to enable adjustment of the case to the size of instrument housed.

Abstract: A digital display electronic meter apparatus is disclosed which is capable of displaying amplitude ratio measurements directly in decibels over its entire amplitude operating range.

Abstract: The present invention comprises a plastic case for housing electronic instruments and the like, having a top and bottom panel with two side panels connecting them. The edges of the top and bottom panels are mounted for telescoping movement in the side panels to enable adjustment of the case to the size of instrument housed.