The soldering iron thermometer is composed of a temperature sensing wire and a meter
If you have a digital multimeter on hand that can measure temperature, and the probe is a thermocouple, that's handy. Because generally this thermocouple is also type K, directly connect the output of the temperature-sensitive wire to the temperature input of the multimeter! The temperature is displayed directly.
If you have a digital multimeter can not measure the temperature, then you can only use its 200mV gear to measure the voltage, and then check the table, converted to temperature values.
Temperature-sensitive line can be used with a white light 191 thermometer, used as long as the use of a good. Sensitive line belongs to the consumable materials, with about 50 times to replace a to ensure accuracy, so it is easy to buy.
Temperature-sensitive line is the Mercedes-Benz trademark shape, the middle of a temperature-sensitive block, leading to the three lines, the end of a circle used to connect the terminal. In fact, it is made of two lines, there are red sets of positive lines, blue sets of negative lines, there is a side of the two lines are entangled together, not as a signal line, mainly used as a support, because the three edges can be supported firmly.
The main job is to make the shelf for the sensing wire.
Buy 3 terminal blocks. If the threads of the terminal block are larger than the loop of the lead wire of the thermocouple, remove the small loop of the lead wire and just rewind a large loop to the size of the threads of the terminal block.
Then take a waste circuit board, compared to the size of a good drill three holes, just a triangle, the terminal installed on the circuit board. And then the temperature-sensitive line three feet connected to the threads of each terminal, tighten the nut on it. And then welded on the line to the multimeter, it's good.
Temperature measurement, the soldering iron head first on the tin, and then placed in the middle of the temperature-sensitive line on the temperature-sensitive block, tin surface and temperature-sensitive block horizontal contact, and a certain degree of strength. Temperature-sensitive block can be on the tin, so it can be fully contact with the iron head, the measured temperature is more accurate. At this time, the temperature of the multimeter temperature gear directly shows the temperature.
If the measured voltage mV value, the following conversion table will be used to convert the voltage to temperature, plus room temperature, is the temperature of the soldering iron. For example, 12.6mV is 310°C. Add the room temperature, say 30°C, and the temperature of the soldering iron tip is 340°C.
In addition, do not use the temperature wire, directly with the multimeter thermocouple to contact the soldering iron head, is possible, that is, the multimeter thermocouple is not on the tin, so can not be completely in contact with the soldering iron head, it will be slightly smaller than the temperature value measured by the temperature wire, but generally only small 2-5 ℃ or so.
