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98 Threads found on edaboard.com: Junction Temperature
Thermocouple voltage can't be processed by PIC directly. Need a DC amplifier with gain of 200 to 250 to fit the 5 V ADC range, also a temperature sensor for cold junction compensation.
There are ADC with internal PGA that can measure thermo couples. ADS1118 has e.g. about 0.2 K resolution and a few K absolute accuracy, also an internal temperature sensor suitable as cold junction reference. That's not mind blowing but suitable for many applications.
Hola I am using a TPS62122 stepup converter. This have junction to ambient thermal resistance set to 114.4C/W and a max load of 75mA. Am I correct that on a PCB which have no extra cu for thermal disipation that when this converter is generating a 3.5V form a 12V supply, the temperature may reach as high as 90C @65mA load when ambient tempera
Inserting a different metal (e.g. connector, terminal strip) into a thermocouple wire will only generate an additional thermo-electric voltage if both end junctions are at different temperatures. This can of course happen, if the connector is mounted in an enclosure wall with different in- and outside temperature. For this reason, dedicated (...)
Any silicon semiconductor junction forward voltage has a temperature coefficient of about -2 mV/K. Asking for a more stable voltage drop is simply ignoring laws of physics. It makes sense to ask for devices with less type variation of forward voltage, specific leakage or current gain characteristics. But forward voltage temperature (...)
Hi Could someone please help me with a problem. I have a PCB that fits in an ABS box and is to be completely potted, top and bottom. I am investigating device failure modes, as I need to ensure that the outside surface temperature does not reach 135C. I've worked out that one SOT23 device may reach a junction temperature of 150C, (...)
Have to agree with Barry here. There are many limitations to accuracy that include the accuracy of cold junction correction, plus the purity of the metal alloys in the thermocouple, plus the accuracy and calibration of the electronic amplifier. Thermocouples have a great many advantages, but absolute accuracy is not one of them. Your best bet m
Max junction temperature = 150*C, use 120 for safety. Tambient = 40 *C, so you have to dissipate 10 Watts across a temperature of 110*C. The thermal resistance of the junction to case is 6.5*C/W, So the case of the transistor will be at 65*C less then the max, i.e. 120- 65 = 55*C. So the heatsink will have to dissipate 10W (...)
Dear friends , I need to make a j type temperature controller . Please suggest me how to proceed , never used one before . 1. I need circuit used for j type thermocouple signal amplification using opamp op07 and diode for cold junction compensation , I have seen temperature controllers using thermocouples in mkt and they use a diode (...)
I am able to read temperature accurately using MCP9600. Its a Thermocouple EMF to temperature Converter. The MCP9600 digital temperature sensor comes with user-programmable registers which can be used to detect multiple temperature zones. I.e. it can be configured to detect when the Hot junction of a (...)
A semiconductor junction conducts better when it is warmed. Therefore its forward voltage becomes reduced. You cannot change it so don't ask why.
​ Electronic component always goes wrong because of exceeding junction temperature, that caused by two reasons: 1. the calorific power of itself is too high; 2. Filling with air in the electronic component that result in bad heat conductivity. At present, there are not any ways to solve this problem except that removed
you really need to use that "sleeve of copper braid" to be your heat sink. otherwise the diode will quickly fail. It is just a silicon diode, and the gold metallization will diffuse into the silicon body if the temperature gets too hot, and the diode will eventually short out. I would mount the diode right at the junction of the shield and radi
Hello everyone, I am doing Thermal Analysis of my device and I need to calculate thermal resistance between junction and Case of my device. All I given in datasheet is junction temperature and Base plate temperature. There is no information given about thermal resistance between junction and Case. So, (...)
junction refers to semiconductor junction (e.g. of a transistor), in other words the chip temperature. The "junction" or chip is the heat source and obviously the hottest point in chain. It's also the most sensitive point.
Enclosed cases are always critical thermal designs. Apart from having to use a large fan to ensure equal distribution of air flow through the greatest possible internal surface of the cabinet, it may also be necessary an additional small fan over the hottest components in order to prevent the junction temperature exceeds the specified limit.
Hello, I've always limited junction temperature of such diodes to 110 deg c in the past, but is it ok if we run the MUR840 diode with Tj=150 degC? The datasheet suggests we can. Its got 4A average in it. MUR840 datasheet
Tj max will specify the max junction temp, the device can withstand ... you have to look into the graphs in DS to see what's the allowed rms current at this Tj. That means you may not be able run at max power what you need at this temp of junction. Also, with or without heat sink, you can calculate what can be the ambient temp for the device operat
It's normally mentioned in the data-sheet of the transistor as SOA ( Safe Operating Area ). Or Rth should be given to calculate package temperature.For instance Rth=500 K/W ( From junction to Free Air) for BC857.If power dissipation 150mW, if ambient temperature is 25C, junction temperature will be 75C so (...)
It doesn't generate an analog signal. The report is entirely digital. I think the earlier versions of the device used two oscillators, one temperature stabilized, the other temperature dependant, the difference in frequencies was used to produce the numeric result. Later versions used an internal bandgap reference, PN junction to sense (...)