Block 3 - lecture 8 Flashcards
Potentiometric sensor?
A coil of wire with adjustable connectors to change the length of the wire
circuit for a potentiometric sensor?
as the feedback resistor in an inverting amplifier circuit
equation for potentiometric inverting amplifier output?
Vout = -Rsensor/R * Vin
capacitive sensor?
- two places move together/apart (distance reduces capacity)
- two plates move over each other (area reduction reduces capacity)
induction sensors?
- permeable core moves through an AC solenoid
- solenoids either side have a current induced, proportional to the distance from the centre
types of level sensors?
- concentric cylindrical capacitor
- above/below surface ultrasonic sensor
strain sensor?
extension (strain) in wire increases the length and decreases the area, thus increasing the resistance
equation for resistance from strain?
resistance change = 2Rstrain
types of motion sensor?
- rectilinear (movement in a direction)
- angular
- vibration
- shock (sharp acceleration)
accelerometer?
mass on a spring
important accelerometer considerations?
- should cover expected accelerations
- should have an natural frequency higher than that being measured