up::[[Sensors]] ## 1. Thermocouples pros: - cheap cons: - not as accurate Probe tip has three types - grounded (rapid but susceptible to electrical noise) - ungrounded ( slow but not susceptible to electrical noise) - open (fast but easily damaged) ## 2. RTD Platinum wire wrapped in ceramic or glass core. Wire will change resistance based on temperature. Because they are resistive devices they are affected by the length of wires that lead to them. Four-wire method is most accurate way to cancel out errors. pros: - high accuracy - low temp performance cons: - slow response ## 3. Silicon Diode Pros - great at cryogenic temps cons - Not so great at higher temps - big knee (controllers use a lookup table to fix this non-linearity) See also: [[Time Constant]]