| ??? 02/25/09 09:42 Read: times |
#162814 - PN junction is affected by Temperature Responding to: ???'s previous message |
It is known that the p-n junction is affected by temperature changes
in a form of e^(KT). A common solution at experimentaional days was to use a NPN transistor with Base direct connected to Collector. The Collector-Emmiter circuit has a coefficient of 2.2mV/°K slope, so using properly biased circuit by current source, it becomes a temperature sensor very accurate, if you encounter the curve path. Thats why Signal Diodes 1N4148, 1N914, Transistors BC547, BC108, maybe used as such. I'm looking for something ready-made, thin, long, insulated, with cables about 1meter long. The Omega site mentioned by Neil has such sensors already calibrated for maximum accuracy. The wiring problem mentioned by Oliver is true that's why there is the need to change the sensors. The I2c TCN75 are already in insulated capsule, but are about 8mm wide and the need is for 4mm. Your suggestions are very helpfull K.L.Angelis |
| Topic | Author | Date |
| Looking for a Temperature Sensor for small and cold places | 01/01/70 00:00 | |
| KTY series? | 01/01/70 00:00 | |
| KTY nice suggestion | 01/01/70 00:00 | |
| Yes, from time to time... | 01/01/70 00:00 | |
| Digital Thermometer with 1wire PWM output | 01/01/70 00:00 | |
Temperature accuracy | 01/01/70 00:00 | |
| Why not a thermocouple? | 01/01/70 00:00 | |
| Thermocouple already used | 01/01/70 00:00 | |
| So do not use a bare one. | 01/01/70 00:00 | |
| Wiring problem | 01/01/70 00:00 | |
| Common Sensor too is a Diode... | 01/01/70 00:00 | |
| PN junction is affected by Temperature | 01/01/70 00:00 | |
| small temp sensor | 01/01/70 00:00 | |
| Thermistor | 01/01/70 00:00 |