摘要:
A laser power meter incorporating an absorber disc with a peripheral thermopile ring, either continuous or segmented, and an additional temperature detection element in the central portion, that enables measurement of beam size. This detection element can be a thermopile element, generally a ring of smaller diameter than the peripheral thermopile used, and located closer to the center of the absorber disc. With this arrangement the beam size can be measured, in addition to measurements of the power and the position of the beam. Alternatively, this centralized detection element can be a single thermocouple junction located at the center of the disc, which acts as the hot junction of a thermocouple pair. The second or cold junction is effectively located on the disc close to the peripheral thermopile. Alternatively, two temperature measuring elements can be used, one at the disc center and one at the periphery.
摘要:
A laser power meter incorporating an absorber disc with a peripheral thermopile ring, either continuous or segmented, and an additional temperature detection element in the central portion, that enables measurement of beam size. This detection element can be a thermopile element, generally a ring of smaller diameter than the peripheral thermopile used, and located closer to the center of the absorber disc. With this arrangement the beam size can be measured, in addition to measurements of the power and the position of the beam. Alternatively, this centralized detection element can be a single thermocouple junction located at the center of the disc, which acts as the hot junction of a thermocouple pair. The second or cold junction is effectively located on the disc close to the peripheral thermopile. Alternatively, two temperature measuring elements can be used, one at the disc center and one at the periphery.
摘要:
To provide for temperature measurement of a solid electrolyte polarographic gas composition sensor, an ac signal is superimposed from an ac voltage source (2) on the applied voltage from a voltage source (1) if the sensor is a polarographic sensor, the ac signal being separated from the output by a filter combination (6, 7), the dc output being evaluated as usual, and the ac output being rectified in a rectifier (9) to obtain a measure of the temperature since the ac resistance (R.sub.alt) is highly temperature dependent (see FIG. 3). The ac preferably is about 10% of the applied dc voltage, so that the voltage swing of the ac potential falls well within the linear range of output current with respect to voltage (see FIG. 2). The output from the ac channel (7, 9) to evaluate the temperature signal can be connected to a control loop circuit (10, 11), including a heater (11) to heat the sensor to maintain a uniform temperature thereof.