How to check integrity with a multimeter
Content
Working in this industry, I learned that a multimeter is vital. One of the most common uses of a multimeter is to test for continuity. In case you didn't know, a continuity test is critical as it checks to see if a wire or loop on the PCB is broken.
Any DYIR'er electrician should learn how to perform a continuity test with a multimeter that can be used to test electrical components and circuitry in a million different ways. Follow the instructions to learn how to check continuity with a multimeter.
Multimeter setting
Move the multimeter dial to the continuity test function to use the multimeter's continuity test function. You should hear a clear beep when the multimeter kit leads touch. Before testing, gently touch the tips to each other and listen for the beep. You must do this to ensure that the multimeter's continuity check function is working properly.
Continuity check
A continuity test determines whether two objects are electrically connected: if so, an electrical charge can flow freely from one endpoint to the other. (1)
There is a break somewhere in the wire if there is no continuity. This could be due to a damaged fuse, poor soldering, or incorrect circuit wiring.
Now, to properly test for continuity, do the following:
- First make sure there is no power running through the circuit or device you want to test. Remove all batteries, turn them off and unplug them from the wall.
- Connect the black lead to the multimeter's COM port. And you must insert the red probe into the VΩmA port.
- Set the multimeter to measure continuity and turn it on. It usually looks like a sound wave icon.
- You must place one probe at each end of the circuit or device you wish to test for continuity.
- Then wait for the results.
Understanding Continuity Test Results
The multimeter injects a small current through one probe and checks if the other probe is receiving it.
It doesn't matter which probe hits which point because the continuity measurement is non-directional, however there are some exceptions, for example if your circuit has a diode. A diode is similar to a one-way electric valve in that it indicates continuity in one direction but not in the other.
The test power passes if the probes are connected in a continuous circuit or in direct contact with each other. The multimeter beeps and the display shows zero (or close to zero). This means that there is a sense of continuity.
There is no continuity if test power is not detected. The display should show 1 or OL (open loop).
Note. Certain continuity mode is not available on all multimeters. However, you can still perform a continuity test if your multimeter does not have a specific continuity test mode.
Instead, you can use resistance mode. This is usually denoted by the symbol Ohm (Ohm). Don't forget to set the watch face to the lowest setting.
Voltage test
When analyzing the performance of electrical and electronic circuits, or trying to figure out why a circuit is not working properly, you need to keep track of various voltage levels.
- Connect the black lead to the multimeter's COM port. Insert the red probe into the VΩmA port.
- Set the multimeter dial to constant voltage mode (indicated by a V with a straight line or a ⎓ sign).
- The positive terminal should make contact with the red probe, while the negative terminal should also make contact with the black probe.
- Then wait for the result.
Understanding Voltage Test Results
Although most multimeters do not have an auto range, you will have to manually select the appropriate range for the voltage being measured.
The maximum voltage it can measure is listed for each position on the dial. Use the 20 volt level, for example, if you intend to measure more than 2 volts but less than 20.
If you are not sure, choose the highest value. However, you may not get an accurate estimate if your range is set too high. On the other hand, the multimeter will just show 1 or OL if you set the range too low, which means it is overloaded or out of range. This won't hurt the multimeter, but we need to increase the range on the dial.
Flipping the probes won't hurt you; this will only result in a negative reading.
Resistance test
The power flow applied to the circuit is used to calculate the resistance. When current flows to the circuit under test, a voltage (resistance) is created. You can use it to find out how well a circuit or component is performing. The lower the current, the more ideal the resistance, and vice versa.
Keep in mind that you will be testing the resistance of the entire circuit. If you want to test a single component, such as a resistor, do so without soldering.
Read on as I tell you how to perform a resistance test with a multimeter:
- Make sure power is not passing through the circuit or component you want to test first. Take any batteries, turn them off and unplug them from the wall.
- Connect the black lead to the multimeter's COM port. Insert the red probe into the VΩmA port.
- Set the multimeter to the resistance function and turn it on.
- One probe should be attached to the end of the circuit or component you wish to test.
Understanding Resistance Test Results
Resistance is non-directional; thus, it does not matter which probe moves where.
The multimeter simply reads 1 or OL if you set it to low range, which means it is overloaded or out of range. This will not affect the multimeter, but we will have to increase the range on the dial.
Another possibility is that the network or device you are testing has no continuity, which means it has infinite resistance. An intermittent connection will always show 1 or OL when checking resistance.
Security
Measuring continuity is simple, but don't let that simplicity get in the way of your security. To protect yourself from shock and to protect the multimeter from damage, follow these guidelines:
- Always wear good quality protective gloves when using the multimeter.
- Always turn off the instrument when measuring continuity.
- If checking continuity is a routine activity for you, make sure you change your multimeter batteries regularly. The buzzing sound reduces battery power faster. (2)
You can find other multimeter test guides in the list below;
- How to measure amps with a multimeter
- How to find a short circuit with a multimeter
- How to measure DC voltage with a multimeter
Recommendations
(1) electric charge - https://www.livescience.com/53144-electric-charge.html
(2) battery power - http://www2.eng.cam.ac.uk/~dmh/ptialcd/
battery/index.htm
