How to Test a Diode with a Multimeter
A diode is designed to let current flow in one direction while blocking it in the other. This simple function makes it useful in rectifiers, power supplies, circuit protection, and many other elect...
When you use a multimeter regularly, the test leads can make more of a difference than you might expect. They affect how easily you can reach a test point, how comfortably you can work in different...
How to Test for Parasitic Draw With a Multimeter
A battery that repeatedly dies while the car is parked may be defective, undercharged, or supplying an electrical load that never shuts off. This guide explains how to distinguish those possibili...
True RMS is a measurement method that determines the effective value of an AC waveform by accounting for its actual shape. RMS stands for root mean square: square the instantaneous values, calcula...
How to Test a Motherboard with a Multimeter
Testing a motherboard with a multimeter can help rule out a weak CMOS battery, an out-of-spec power supply, or an obvious power-rail fault. It cannot confirm every motherboard failure. Start with t...
How to Test a Transformer with a Multimeter
What Is a Transformer? A transformer transfers alternating-current (AC) electrical energy between circuits through electromagnetic induction. It can raise or lower voltage while keeping the primary...
Ceramic vs. Glass Multimeter Fuses
If a multimeter's current function has stopped working, a blown internal fuse may be the reason. The tempting question is whether to replace it with a ceramic or glass fuse. For a multimeter, howev...
How to Fix a Breaker That Keeps Tripping
A circuit breaker trips to interrupt power when it detects a condition that could overheat wiring or create another electrical hazard. A single trip can happen after a temporary overload. Repeated ...
How To Test Car AC Compressor With Multimeter
A multimeter can help you find electrical faults that prevent a car AC compressor from operating. It cannot confirm refrigerant charge, internal compressor damage, or every computer-controlled faul...