Multimeters: An Electrical Engineer's Right Hand
A multimeter is handy for measuring electricity, like a ruler measuring distance, a stopwatch measuring time, or a scale measuring weight.
Multimeters are used to measure current, resistance and voltage. Modern multimeters have significant upgrades and can measure frequency, capacitance, transistors hFE and temperature.
Some multimeters have a continuity check feature that emits a loud beep if two things are electrically connected. This function is super helpful if, for instance, you are building a circuit and connecting wires or soldering; the beep lets you know everything is connected correctly. This feature also helps you ensure that two things are not connected to help prevent short circuits.
Another feature some multimeters have is a diode check function. A diode is like a one-way valve that only lets electricity flow in one direction. The exact use of the diode check can vary from multimeter to multimeter. If you're working with a diode and can't tell which way it goes in the circuit, or if you're not sure the diode is working correctly, the check feature can be pretty handy.
Advanced multimeters might have other functions, such as measuring and identifying other electrical components, like transistors or capacitors.