Measurement, Metrology, Quantities and units, systems and units, SI. Standards and common instruments. Measuring Sources: Sources of direct current / voltage, sources of AC current / voltage, variable transformers, function generators, frequency synthesizers, calibrators. Analog instruments: ammeters / voltmeters, universal instruments, wattmeters, oscilloscopes. Digital instruments: counter / timer / frequency meters, multimeters, oscilloscopes. Sensors and transducers. Auxiliary equipment: rheostats, potentiometers,decade boxes of resistance, capacitance and inductance. Virtual instruments. Distant laboratories. Serial, parallel and equivalent networks. Linear potentiometer and a fixed source. Logarithmic potentiometer and a fixed source. Determination of internal resistance of the real voltage source. Thevenin's theorem. The current source and the variable resistors, linear and logarithmic. Fine-tuning of the desired resistance in three ways. Current divider. Voltage divider. Amplitude and phase diagrams. Integrator and differentiator in pulse mode. Temperature measurements using a thermosensitive resistor.