Ch6 Bioinstrumentation/Biosensors

Flashcards reviewing key vocabulary terms and definitions related to bioinstrumentation and biosensors.

Bioinstrumentation

The use of instruments that interact with or measure biological phenomena, crucial in healthcare for diagnostics, therapy, and assistive technologies.

Diagnostic Bioinstrumentation Devices

Provide data to guide medical decisions (e.g., ECG for arrhythmias).

Therapeutic Bioinstrumentation Devices

Directly interact with physiological processes (e.g., defibrillators).

Assistive Bioinstrumentation Devices

Restore lost functions (e.g., prosthetic limbs).

Measurand

The physical or physiological quantity to be measured (e.g., temperature, biopotentials).

Transducer/Sensor

Converts the measurand into an electrical signal.

Variable Conversion Element

Adjusts the signal form (e.g., from resistance to voltage).

Signal Conditioning

Amplifies and filters the signal for accurate reading.

Output Display

Shows processed data for interpretation.

Analog Signals

Continuous signals that can take on any value within a range.

Digital Signals

Discrete signals that are easier to process, store, and transmit.

Resolution

Smallest detectable input change.

Accuracy

How close a measurement is to the true value.

Precision

Consistency across repeated measurements.

Sensitivity

Minimum input change that causes a detectable output.

Signal-to-Noise Ratio (SNR)

The ratio of useful signal power to background noise.

Systematic (Bias) Errors

Errors due to miscalibration, fixed offsets, or design flaws.

Random (Precision) Errors

Errors caused by fluctuations in the system or environment.

Biopotentials

Electrical signals generated by the body (e.g., brain, heart, muscles).

Differential Amplifier

Amplifies the difference between two input signals, removing common-mode noise.

Instrumentation Amplifiers

Amplifiers with multiple stages, high input impedance, and excellent noise rejection.

Active Sensors

Sensors that require external power to operate (e.g., powered strain gauges).

Passive Sensors

Sensors that generate their own signal in response to changes (e.g., pressure indicators).

Electrodes

Convert ionic current to electric current.

Potentiometers

Measure displacement via resistance changes.

Strain Gauges

Track deformation by resistance variation.

Capacitive Sensors

Detect motion via changes in capacitance.

Piezoelectric Materials

Generate voltage under mechanical stress.

Wheatstone Bridge

An electrical circuit used to measure small changes in resistance.

Capacitive Sensors

Sensors that use two conductive plates separated by an insulator to measure motion, position, or force.

Piezoelectric Sensors

Sensors that generate voltage when mechanically deformed; used in pressure sensing and accelerometers.

Inertial Measuring Unit (IMU)

A device that integrates multiple sensors (accelerometer, gyroscope, magnetometer) to measure movement, velocity, and orientation.

Accelerometers

Measure acceleration forces using piezoelectric, piezoresistive, or capacitive principles.