A Digital Multimeter And How To Use

Put this tool in your boat. This will save you a lot of frustration and time. Trust me !!!!!! Solve electrical problems: Using a digital multimeter

Do you need a digital multimeter? Yes! Once you understand the basics, it can preserve you time, money and hassle when identifying the source of a power problem.


Several boats have AC power, which can kill. Make sure all AC power is off the boat before starting work. Disconnect or disconnect the noise-power connection, inverter and generator. Be confident of your abilities and, if in doubt, consult a qualified marine electrician.

Your brand-new Bilge pump pipes a fuse every other trip, and your VHF blur whenever you try to send it. An easy way to find the source of your problem is to take out your digital multimeter and do an electrical probe. But first, read the instructions and make sure you understand them.

If that doesn’t happen, it’s time to dump her and move on. Also, it would help if you had a basic idea about wiring and what is dangerous. This is the difference between AC and DC electricity and wiring in your boat. Got it? Great! Now, let’s examine the basics of using a digital multimeter to measure DC, resistance and voltage.

The rate of current flowing through the wires in your boat is current. Think of it as the foot of a garden, where the wind is flowing out. It is measured in amps.

When a current is interrupted due to a bad connection or a device like unwanted shaped wiring stops working or at least stops working like this, it is known as resistance – like a hose. And the voltage is somewhat similar to the amount of water pressure in the hose, to put it very simply. The more stress, theoretically, more energy can be produced.

A digital multimeter can be used to measure all this and much more. Some units perform more complex, more complex tasks than others. Someone has different features (e.g., auto-ranging vs. manual) to measure the same functions better. Some digital and some analog (a needle).

Most of us have general needs, such as fundamental current, resistance and voltage determination and no need to spend extra money on complex features. However, it is advisable to spend money on quality regardless of the use, as electricity can be hazardous.


When you have a problem with onboard electronics, the first thing to check is that you have a suitable power source. In a boat, a 12-volt DC power is supplied by a battery or batteries, so that is your starting point.

The digital multimeter I am using has several capacities, so since I measure 12 volts, I turn the meter scale to read DC volts, especially the 20-volt range, which is the closest to the voltage I have to read. (Meters with auto-range can adjust this automatically)

To get the right lesson, first, turn off your battery charger. Then check that the black probe is plugged into the black “normal” reception of the meter and the red examination is announced into the “voltage” reception.

Now touch the red probe on the positive (red) battery terminal and the black probe on the negative (black) terminal and note the voltage.

A reading of 12.65 volts or more registers a full charge, 12.3 volts a 75% charge, 12.2 a 50 percent charge and 12 volts a 25 percent charge. If the battery falls below 12 volts, it is effectively dead and needs to be recharged or replaced.

Measuring Current

 If the problem you are having is not getting the devices to turn on but can continue due to tripping a circuit breaker or blowing a fuse, you are drawing too much current through a given circuit. Replacing old boats with new, energy-hungry devices may exceed the capabilities of the original courses.

Here’s how to use your digital multimeter if you don’t have good documentation on how many amps to draw on a given device. This test uses the meter to complete the circuit itself. An excellent place to put the meter lead-in is circuit protection (fuse block). If there is a fuse, remove it – the meter will be measured on both sides of the fuse block.

Switch from the circuit you are testing, then set your meter selector switch to DC amp. You will probably need to move the meter’s red probe to the “amp” plug. (Some meters only read a minimal amount of amps See See you have enough))

Disconnect a wire where you measure or hold the fuse holder or black lead on one side of the wire and the other’s red information. Again, be careful not to touch the leads together. Finally, switch your body parts to be careful not to complete the circuit. The meter will give you a lesson in MPS for recording.

If the total amp draw of a circuit exceeds the safety rating, the breaker will trip. Measure a load of all the devices in the given circuit and connect them to see if it is overloaded. If so, you’ll need to upgrade cables and over content protection.

Continuity Check

 There must be a perfect circuit from the power source to the powered thing and back to the power source for electrical equipment to work. Sometimes, even if everything looks OK, those bulbs, fans, or other widgets will not work correctly. This may be due to a continuity problem – circuit break. Using your digital multimeter, you can determine if a bulb is blowing out or if a fuse is wrong, or make sure there are electrical connections to several other components.

To test the circuit, make sure your power is off. Start by setting a digital multimeter on the ohms scale, usually represented by the Greek letter defined (omega). An ohm is a measure of resistance. When there is an altercation in the circuit, your meter shows “OL,” which means “overload” or “open-loop,” meaning the crack in the rotation. When the course is complete, the meter will show a minimal reading, indicating that all is well.

If it is registered more than a few ohms, it may be due to a bad connection to the lousy wire’s circuit or unwanted resistance. Carefully inspect all circuit components and address them.

Five Ways to Use A Digital Multimeter

What do you do when your VHF or live-well pump is dead? Start sleuthing with the help of a digital multimeter.

 A DVOM uses two leads: a black headliner and a red pointer. The plugin you are black.

Lead to the device’s “COM” port or common terminal. Similar to the negative terminal, this is the top of the reference.  Plug the red lead into a port that matches the setting you selected on the DVOM selector switch.

In some DVOMs, these are combined in a single port; Other devices provide separate ports for amps, volts and ohms. To understand what is going on in your boat’s electrical system, the single best tool is a digital multimeter, sometimes called a DOOM (digital volt-ohm meter).

Available as little as 20, a DVOM reveals three main things about an electrical circuit: electrical potential (voltage), electrical current (amperage), and electrical resistance (ohms).

Voltage is like the pressure of hose water. Currents are the rate of flow – for example, say, water passing through a nozzle.  And the resistance hose or even the hose itself: the energy that limits the flow.

What is the circuit? It is a chain of six components that power a device: a power source (battery or distribution panel), a conductor, a switch, circuit protection (a fuse or circuit breaker), a tool and a way back to the ground (another cable).  If VHF only works non-stop or not at all, then one of these six elements is likely to frustrate you. DVOM lets you sort out what’s wrong. Here’s how to go about it.

Open-Circuit Voltage Test

The first step is to use an open-circuit voltage test to determine the battery’s charge status to determine if the boat’s power source is right and how much voltage it can supply. 12.6 volts or more reading shows a full charge; 12.3 volts, 75 percent charge; 12.2 volts, a 50 percent charge; 12.0 volts, a 25 percent charge. Readings below 11.7 volts indicate a discharged battery. Regard the steps below.

Switch the DVOM selector to DC volts (scale for less than 20 volts). Turn off all circuits on the boat (switch off the battery selector). Engine and charging system off.

Hold and hold the DVOM black lead (COM port in DVOM) on the batch’s negative terminal and place the red information (DC volt port in DVOM) on the positive terminal. You should read a voltage that indicates the state of charge of your battery. Could you write it down? If it is above 12 volts, continue the next test. If not, charge the battery.

The Voltage-Drop Test

Voltage drop is the imminent loss of electrical potential through the circuit. The American Boat and Yacht Council (ABYC) allows a three percent voltage drop on critical circuits (NAV lights, VHF radios) and a ten percent voltage drop on all non-critical circuits.

A higher voltage drop indicates a faulty connection, garbage terminal, or underside wiring, which needs to be corrected. The first test should have mentioned your battery voltage. Now you need to test the voltage at VHF.

The battery and circuit you are trying (flip the appropriate breaker on the DC panel). All other courses are closed. Convert the DVOM selector to DC Volt. In VHF, touch your red lead on the positive terminal, black lead on the opposing side.

Compare the results with your voltage at the power source. A drop of more than 0.4 V (A BYC considers a VHF radio to be a critical circuit) or a 1.2 V V of any circuit will send you screwing to clean the terminals and check adequate cable gauges. If the voltage drops to zero, you have a continuity problem.

Checking Continuity

A standard electrical fault is “an unwanted opening” – an unwanted break in the circuit – that impedes the flow of electricity. It could be something as simple as a blown a fuse, or it could come from something more complex, like a broken or highly corrosive conductor, or from a loose or separate connection.

Continuity describes a circuit in which it is closed, as it is designed. To find out if there are breaks in your course:

Move the DVOM selector to ohms.

Check the DVOM battery. You should see “OL” for “overloaded” or having no continuity by separating the leads. Now touch the vertices together and you should hear a beep or a value near the “0” of the meter for continuity. If you do not get it, replace the DVOM battery.

Close the circuit to test.

Attach a certificate to your discussion certificate (say, VHF re-running information from the lookup panel). If you do not have temple divinity limits, you do not have to fill the whole part.

Connect your product.

Saturn must read a bit or a meter reading the direction.  “OL” overloaded: not face to face. Little girls do not die. No one should contact your test. It would be best to go for this test with a swollen fuse and a treaded circuit (check it) and not disconnect the power.

The circuit is broken and the device is confronted. If you don’t get some parts, go back and check a loose or garbage connector, or giggle the test, or the region you tested contains part of it. When something goes wrong, the pressure is not expressed when it is applied.

Measuring Current Using Leads

If the problem is yours, not getting the devices to turn on but running them, you are drawing too much current (amps) through the given circuit. Fitting old boats with new, power-hungry devices may exceed the capabilities of the original courses.

If you do not have adequate documentation on how many MP to draw the given device, here is how to find it. Use a pair of meter leads that end up in heated alligator clips. It would be best to disconnect the power lead somewhere in the circuit; The meter will complete the course. An excellent place to put the meter lead-in is circuit protection (fuse block). If there is a fuse, remove it.

Close the circuit you are testing.

Set the selector of your divorce to DC amp at the correct scale.

Disconnect the wire where you will measure; Alternatively, remove a fuse from its container.

Clip the black lead to the terminal, almost like the battery. The red leads to the other.

Switch the circuit, being careful not to let your body parts complete the course.

The meter will give you a lesson in MPS for recording. If the total amp number of a circuit exceeds its safety rating, the breaker will pop up. Measure all devices in the given course to see if it is overloaded. An amp clamp can contain current without disconnecting the circuit.

Current Test Using An Amp Clamp

Some new digital multimeters come with a feature called an “amp clamp” that allows you to measure current without disconnecting the circuit. However, there are still several strategies. First, when measuring DC, make sure you understand the directional element of your DVOM.

Some batteries come with a plus sign and an arrow showing which side of the meter facing the positive terminal will be displayed—your manual advice. Second, you only need to measure the current through one conductor – especially a positive conductor (usually red).

You can sometimes find dual wires in marine DC systems, which have positive and negative (usually black or yellow) conductors in the single-shell; You need to separate them to do this test.

  1. Identify the positive conductor of the circuit you’re testing.
  2. Set your digital multimeter to DC amps at the proper scale.
  3. Open the jaws of the amp clamp, then encircle the positive conductor. You should get a reading to record.

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