Many multimeters have the ability to test amperes (A) and can be used as an ammeter. Even if you’re using a multimeter, the black lead always connects to the COM port. Make sure you’re using the correct ports! Improper wiring could cause the ammeter to burn out later.
If you’re using a multimeter, you may only see a port labeled VΩmA or something similar. Fit the red lead into that port. It works with all of the multimeter’s functions. If your device has a separate port like VΩ, it is used to test voltage and resistance
If the display stays at 1, the meter could be broken. It happens sometimes when the fuse burns out from a strong electrical shock. If your meter doesn’t have a resistance setting, you won’t be able to test it this way. Try wiring it into a circuit. If it doesn’t react when the power is on, then it is probably burnt out.
An example of a DC current is a battery circuit. The electricity flows from the positive terminal, around the circuit, and back to the negative terminal. AC circuits are used to route power in homes, office buildings, and other areas that require high amounts of electricity. Note that some ammeters only test AC or DC. If yours is like this, it will most likely be labeled and you won’t see different settings to choose from. AC is often represented by a squiggly line, while DC is represented by a straight line.
Many ammeters have different settings from amps to milliamps and microamps. For comparison, an amp is 1,000 milliamps. A basic circuit with a small battery can be measured in milliamps. You could set the meter at 2 A, then turn it down to a milliamp setting until you get a consistent readout. More powerful circuits, such as the ones in your home, are better measured in amps. Many ammeters automatically calculate the range. If your meter doesn’t have range settings, then you don’t have to worry about setting it yourself.
For example, if you’re testing a home circuit, shut off power at the circuit breaker or fuse box. The box is usually hidden in an out of the way spot, such as in the basement or garage.
For example, if you’re using a battery to light up a small bulb, you might detach a wire from the bulb. You could then fit the ammeter between the wire and bulb. If you try to touch the probes to a complete circuit, you will most likely short-circuit the ammeter. Ammeters have little resistance, so the electricity has to pass through it in a very specific way to prevent it from burning out.
For example, you could connect the black probe to a wire leading toward the negative terminal on a battery powering the circuit. You could also touch it directly to the battery terminal. For home circuits, connect the probe to the exposed end of a black wire leading toward your home’s electrical supply.
For instance, if you have the ammeter between a battery and a lightbulb, the red probe may connect to the lightbulb. The black wire can touch the battery’s negative terminal or a wire connected to it. If you’re working with a battery, don’t connect both probes directly to the battery’s terminals. It may cause the ammeter to burn out. Keep in mind that the wire coloring scheme can differ from place to place. However, black usually indicates a negative current and red indicates positive one.
When you’re done, turn off the power again before putting the circuit back together.
If you have a plug-in clamp, it will be color-coded like the regular probe leads ordinarily used to test amperage. Plug the black lead into the COM port and the red lead into the A or VΩmA port. Clamp-on ammeters are a more advanced kind of device that can read electrical currents without you ever having to take apart a circuit. It is even easier to use than the older digital models.
The main wires to test include the black and red or white ones. These wires are the ones that often conduct the full electrical current in a circuit. This coloring scheme can vary depending on where you live, however. The great thing about clamp-on ammeters is that you don’t have to detach the conducting wires at all. As long as the wires are well-insulated, you don’t even have to turn off the electricity. However, remember to avoid touching exposed wires or other metal components that could shock you.
Most clamp-on ammeters detect both AC and DC current, so you can use the same dial setting. Some ammeters have a few range settings. Make sure you’re using the correct one. Generally, start with the largest setting and turn the dial down if you expect a weaker current. Keep in mind that clamp-on ammeters are usually multimeters that also test resistance and other measurements. Make sure you’re using the correct settings for ammeter mode.
The ammeter works by detecting the electrical field around the wire. It is just as accurate as one you have to wire into the circuit. Keep in mind that wires of a different color can give you different readouts. The black and red power wires, as well as white neutral wires, will show you the true power of the circuit. Other colors, such as green ground wires, don’t conduct the full current.
