3.9 Sensors and their conditioning

Outcome 9 of 9 in domain 3 · Semiconductors and analog

The sensor family, the signal each gives, and the clean path to the converter.

My targets

I declare:

Classify sensors by what they output: resistance (thermistor, strain gauge, photoresistor), voltage (thermocouple, Hall), current (4-20 mA), frequency or digital (I²C, pulses), and say what each requires.
Measure a temperature three ways (thermistor, thermocouple, integrated sensor) and compare accuracy, range and price.
Measure a current by shunt and by Hall effect, and say when one rather than the other (isolation, high current, DC).
Condition a signal: bridge and instrumentation amplifier for a gauge, divider and filter for a voltage, overvoltage protection at the input.
Linearize a thermistor (table, Steinhart-Hart or parallel resistor) and verify at two known temperatures.
Read a position sensor (potentiometer, encoder, Hall) and a light sensor, and choose for a given project.
Diagnosis: a measurement that drifts with temperature or time, the sensor, the conditioning or the reference; the tests that decide.