Yleismittaria

A yleismittari (Finnish for multimeter) is a handheld electronic measuring instrument used to assess electrical quantities in circuits. It combines several measurement functions in one device, allowing quick checks without swapping tools.

There are two main varieties: analog multimeters, which use a moving-coil meter with a needle, and digital multimeters (DMMs), which display results on a numeric screen. Modern yleismittarit are typically digital and many are auto-ranging, meaning the device selects the appropriate measurement scale automatically.

Typical measurements include DC voltage (DCV), AC voltage (ACV), DC current (DCA), AC current (ACA), and resistance (ohms). Higher-end models add continuity tests, diode tests, capacitance, frequency, and sometimes temperature or transistor testing. Some multimeters offer true RMS measurement, which provides more accurate readings for non-sinusoidal signals.

Construction-wise, a yleismittari features a front panel with a rotary switch, a digital display, and input jacks such as COM and VΩmA (for voltage, resistance, and low-current measurements) as well as a separate 10 A jack for higher currents. Test leads with banana plugs connect the device to the circuit under test.

Safety considerations include adherence to the instrument’s category ratings (CAT) and voltage/current limits, proper use of the correct input jack, and avoiding measurements beyond the device’s specifications. Regular calibration and proper probe handling help ensure reliable readings.

Historically, the multimeter evolved from early analog instruments in the mid-20th century to compact digital models that are now standard in electronics, automotive work, and education.