Multimeter what is cx

So if I were to set the knob to millivolts 0. In any case, you might be asking why you would need to test the voltage of something in the first place. However, if it were to read 1. In a more practical situation, you could do this type of measuring on a car battery to see if it might be dying or if the alternator which is what charges the battery is going bad.

A reading between Furthermore, start your car up and rev it up a bit. Testing the current draw of something is a bit trickier, as the multimeter needs to be connected in series. Above is a crude mockup of what this would look like with a basic clock running off of a AA battery.

On the positive side, the wire going from the battery to the clock is broken up. We simply place our two probes in between that break to complete the circuit again with the red probe connected to the power source , only this time our multimeter will read out the amps that the clock is pulling, which in this case is around 0. If you need to see whether or not an outlet is working, use a non-contact tester instead.

Next, make sure the circuit is unplugged and has no power. You can also test that the continuity feature works on your multimeter by touching both probes to each other.

This completes the circuit and your multimeter should let you know that. And the horns have zero Volts across them so they are silent. Wires are not supposed to have any significant voltage drop across them, so the wiring from points 7 to 8 probably has a fault.

In fact, this is a real-life example of a failure that had occurred with the horn wiring on a GL The wire feeding power to the horns had an internal break where shown. The fault location corresponds to point 8 on the simplified wiring diagram. This specific problem is actually fairly common with GL's. The horn wire harness flexes in the wind, and the point of highest mechanical stress is where it attaches to the horn.

The failure could have been prevented if a wire tie had been used to secure the cable harness so it would not flex. Let's return to the simplified wiring diagram. You may be wondering why some items have a voltage drop across them and others don't. Basically, if there is no current flowing through an item with finite resisitance then there will be no voltage drop across it Ohm's law. Recall that this is a simplified wiring diagram and circuits unrelated to the horn are not shown.

The nonzero voltage drops are due to currents associated with the other circuits not shown that just happen to be flowing through shared components main fuse, ignition switch, etc. Measuring the voltage at every point in a circuit and then sitting down to analyze the situation is both inefficient and not necessary. A "divide and conquer" approach could lead to a diagnosis much faster. An initial measurement could be taken at some place near the middle, say point 5. The results would be the basis for where to take the next measurement.

In this example, point 5 has On the other hand, point 9 would be a good candidate. This simplified circuit is for the GL headlight wiring. Only the low beam wiring is shown, and only a few voltage measurements are provided.

The voltage across the headlight is Unless the bulb is burned out, it should be glowing brightly. Now consider the case where the headlight is not working and the following measurements are obtained:. In this case, the majority of the voltage is being dropped across the dimmer switch and the logical and correct conclusion would be that it is defective. But note that the voltage drop across the headlight is not zero, so some small current must be flowing through it unless it is completely burned out open.

It follows that the dimmer switch has not failed in a completely open state, but in a high resistance state. Anyone who has probed a headlight connector with a multimeter knows it can be difficult to access. So why not simply unplug the connector and measure the voltage on the connector to see if there is any power getting to the headlight? With the fault condition unchanged, the result would probably resemble this:. With the headlight disconnected, there will be no current flowing through the dimmer switch.

And since it has a finite resistance even if very high , the voltage drop across it is essentially zero. The incorrect conclusion from this would be that the headlight must be bad - after all, it is getting voltage to it! The major point is, measurements can be expected to change if the circuit changes. Care should be taken not to disturb or modify a circuit while trying to troubleshoot it or erroneous conclusions are likely.

Point 14 on the diagram represents where the main wiring harness is grounded to the frame. It should now be obvious why it is so important to have a good solid connection at this location. The wiring diagrams in the factory service manuals are significantly more complicated than the simplified ones shown in these examples. Complicated diagrams can be very intimidating. I often find it helpful to sketch out a simplified diagram before jumping deep into a circuit - remember how the saying goes about not being able to see the forest for all the trees.

However, the voltage node troubleshooting concept introduced here can be applied to even the most complex circuits. This site is backed by Number 85 , who provide the hosting. If you need a website done, get in touch with them. Cookies help us deliver our services. By using our services, you agree to our use of cookies. Jump to: navigation , search. Thanks to Dave F for the following information. So, when using a Cen-Tech digital multimeter to check for Voltage, ensure you observe the general safety precaution.

Furthermore, inspect the multimeter to ensure it is in good working condition such as the probe especially. Ensure the probes are well insulated so that you would not come in contact with the current directly. Lastly, make sure you use the right function of the multimeter for the right purpose.

To set the function of the multimeter to measure an electrical value, use the selection knob. In this case, where we would measure Voltage, turn the selection knob to either AC voltage or DC voltage as the case may be. Use the section that has a V with a straight line to measure DC voltage. Likewise, use the part that has a V with a wavy line to measure AC. DC voltage is the type of Voltage observed in batteries, while AC voltage is the one supplied to our home sockets.

At this stage, plug in the probes to the ports on the Cen-Tech multimeter. There are different ports on the multimeter, sometimes three or four, used for measuring various parameters. Although if you twist these wires, you will still get the same value, it would be the negative counterpart.

Now that you have made all the necessary adjustments, all you have to do is connect the probes on the live and neutral wire for AC voltage testing. Note that nothing terrible will happen when you twist the black wire with the red wire. Your voltage reading will become a negative number of the actual result if you switch it by mistake.

At this stage, your reading will be displayed on the screen. Depending on the model of the Cen-Tech multimeter, you have, but most often, you would get your result in three or four significant figures. If you want to ensure your Cen-Tech heavy-duty digital multimeter lasts, then proper maintenance is paramount.

Here are some maintenance tips that will help keep your Cen-Tech digital tester in good shape:. In conclusion, using a Cen-Tech digital multimeter to measure Voltage is straightforward once you have a good grasp of how it works. With the CenTech digital multimeter, troubleshooting an electronic device has become so direct. And the ability of the Cen-Tech digital multimeter to measure different electric values makes it even more useful.