Measurement units. Calibration of measurement instruments and sensors. Typical measurement chain. Theory of error propagation, calculation of systematic, random and total errors. Instruments and sensors characteristics and accuracy class. Types of sensors / transducers. Signal conditioning circuits, Wheatstone bridges, operational amplifiers and applications. Digitization and signal encoding, A/D signal converters. Measurements of electrical quantities, voltmeter and amperometer measurement error, power measurements in three-phase networks. Operational principles of analog measuring instruments, electrodynamic instruments, moving coil, and moving iron instruments.