![]() 1The dreadful P2N2222 is about to strike again.Share edit delete flag edited 17 mins agoanswered 5 hours ago tlfong01 1,01844 silver badges77 bronze badges Below is the first spy report coming back.Īppendix C – 2N2222 Based Temperature Sensor SpecĪppendix D – 2N2222 Temperature CoefficientsĪppendix F – Warning on 2N2222’s non standard pinout (4) Low Voltage Temperature Sensors TMP35/ TMP36/TMP37 Data Sheet – Analog Devicesīefore the 2N2222 faking team attacks the real thing, they need to get to know their enemy. (3) TMP36 Voltage Output Temperature Sensors Datasheet – Analog Devices (2) TMP36 Voltage Output Temperature Sensors Overview – Analog Devices (1) P2N2222A Amplifier Transistors NPN Silicon – On Semiconductor We need to design a circuit to perhaps measure the voltage across a resistor when β and Ic changes and calibrate it. The current gain β is about 150 at 25☌ and increases to 200 when temperature rises to 50☌, and decreases to 100 when temperature drops to 0☌. You see that the DC current gain β(hFE), and collector current Ic changes when temperature changes in the range of 0☌ to 50☌. ![]() Now let us first look at the temperature dependent part of the 2N2222 characteristics, and see if it is worth doing an experiment or feasibility study. Yes, no problem, though not a very precise one, and you need the help of an ADC, such as MCP3008/MCP3201. 2This is the only answer so far that is actually an answer to the question, rather than a science experiment – BeB00 5 hours agoĬan 2N2222 transistor be converted to a temperature sensor, such as TMP36?.It might be possible to look at the various properties of 2N2222 transistor and correlate it to temperature, but that seems not practical for your application share edit follow flag answered 6 hours ago syntax 5922 bronze badges You might have them confused because they both can come in TO-92 package. TMP36 is specifically a temperature sensor, not an NPN transistor like the 2N2222. You want the bias current to be much higher than the ADC leakage current. – mkeith 3 hours ago I think maybe 10uA is enough, but I guess it depends on the ADC leakage current spec. ![]() And I am not sure but I think maybe a couple hundred microamps will give sensitivity of more like 1.8mV per degree. Lower bias current will give slightly higher sensitivity.
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