sang jawara

Arga Dwi Arfiyanto

Ek 2C / 04

Electronic Instrument

Good morning Mr. Sasongko and my friends. Thank you for the time that was given to me, in this second presentation, I will explain about the electronic instrument. Instrument that I will explain is the infrared thermometer.

I will explain step-by-step, the first is understanding, and next is working principles, and the last is certainly instrument itself.

Okay, first I will explain about the function or use of these tools. Infrared thermometer can measure temperature without physical contact between the thermometer and the temperature where the object is measured. Thermometer is on the surface of the object and directly provide the temperature readings. This tool is especially useful for measurements in the hearth or the surface temperature and so on.

Infrared thermometer can be used to measure the temperature where conventional sensors can't be used or can't show an accurate reading, such as the following:

· When the measurement is required on a fast response, such as measurements on a moving object (ex: rail crossing, machinery moving or conveyor belt).

· When non-contact measurement is needed because of contamination of materials or hazardous materials (such as: high voltage).

· When the distance is too far or high.

· When the temperature is too high for thermocouple or other contact sensors.

· Objects in a vacuum condition or on the other controlled atmosphere conditions.

· Object is around by electric field (such as induction heat)

Then, I will explain about the work principles or the way to operated this infrared thermometer.

To operation thermometer non contact or infrared thermometer is very simple. Infrared thermometer (such as a gun) is aimed directly to the surface where the temperature must be measured. the results of measurement just read directly from the panel.

Thermocouple (contact thermometer) consists of two metals that are not same, merged into one at the edges. When combined the two metals be heated or cooled, the voltage will Proposed that can be correlation again to the temperature. Probe is inserted into the flow of liquids or gas to measure the temperature, for example: waste gas, outside air, hot water. Probe types like leaves used to measure the surface temperature. In almost all cases, thermocouple give directly readings on the desired unit(degrees Celsius or Fahrenheit on the digital panel)

Picture 1-1. Infrared thermometers

A basic principle of infrared thermometers is that all objects emit infrared energy. The heated of objects, then the molecule will more active and more the infrared energy that emanated. Infrared thermometer consists of a lens that focuses to collect infrared energy from the object to tools detector. Detector will convert the energy into an electrical signal, which strengthen and weaken and displayed in the unit temperature after the corrected of the variation temperature Ambient.

INFRARED PYROMETER

The working principles of infrared sensor using a photo transistor and led infrared. Photo transistor will be active when exposed to light from the infrared led. Between Led and the Photo transistor separated by a distance. Far or proximity distance is affect the intensity of the light that received by photo transistor. When the photo transistor and the Led is not obstructed by objects, then the photo transistor will be active.

Transistor BC 547 will be not active because there is no current flow to the base of transistor 547 BC. Because the transistor is not active, so there is no current that flows from the collector to emitter so causing transistor BD 139 is not active and the output have logic '1 'and the Led out. When the photo transistor and Led obstructed by objects, photo transistor will be is not active, so transistor 547 BC will active because there is flow into the base transistor 547 BC. With transistor in the "on" state, the current flows from collector to emitter causing transistor BD 139 on and the output will be logic '0 'and Led lighting. With transistor in the "on" state, the current flows from collector to emitor causing transistor BD 139 on and the output will be logic '0 'and Led lighting.