Abstract: A method and apparatus for testing three wire handheld soldering irons by touching the iron's tip to a single point sensor to measure (1) tip temperature (2), tip voltage to ground and (3) tip resistance to ground.

Abstract: A thermopile detector means for a temperature measuring instrument physically and electrically configured to supply an output signal which indicates target temperature substantially independent of the influence of ambient temperature changes. The detector means includes a first thermopile device exposed to radiation from the target and a transducer means, preferably a second thermopile device, shielded from the target and connected in series opposition to the first.

Abstract: A portable, battery operated noncontact temperature measuring device including a lens for collecting infrared radiation and a thermopile for producing a signal indicative of the intensity thereof. The thermopile signal is amplified, linearized and summed with an ambient temperature signal derived from a temperature responsive element, e.g. a diode chip mounted immediately adjacent a cold junction of the thermopile. The resulting composite temperature signal is then processed and displayed. The ambient temperature signal is also utilized to control the impedance of a dual field effect transistor, which in turn controls the gain of the amplifier. Thus, temperature induced variations in the responsivity of the thermopile are compensated by corresponding changes in the gain of the amplifier.

Abstract: Temperature dependent and reference time intervals are simultaneously generated and differentially combined to provide a temperature signal that is employed to generate a probe linearization signal for combination with the temperature signal and digital display. A low resistance platinum probe carries a low current in a timing circuit having a small capacitor charging to a relatively high voltage to provide a high gain for temperature to time conversion circuitry. A continuous real time probe linearization signal is computed for large temperature readings by a double integration circuit having an adjustable readout time for determining the magnitude of the twice integrated temperature signal.