Monday, August 12, 2013

How to use a Multimeter to test for continuity and Voltage.

INNOVA 3320 Multimeter

If you are into Gadget repair or you are Just the type of guy to dabble in the repair field, one of the most invaluable tools to have is a Multimeter. A multimeter is basically a device that gives the end user a great deal of features that they can use to trouble shoot and repair gadgets,home electronics and much more. If you are new to Multimeters the three(3) key features I will be showing you today will get you well on your way to mastering the Multimeter and solving some common gadget or computer issues that would have you going to the store to substitute parts to see if you can pinpoint the source of what is often a simple fault.

The meter we will be using today is the: Innova 3320, this device is really an automotive model but due to its low price and the fact that most Multimeter once you know how to use them are basically the same, the only difference being that higher priced units give a more fine tuned and precise measurement. But for now the basic model will do fine and this Multimeter works on electronics as well as it would on a car.

If you are interested in getting one, the link can be found here

Ok then lets move on to the key test tests that will launch your mastery career:

Test #1: Continuity In Wires

Continuity is a God send on Multimeters and basically is fancy way to say that this test allows the Multimeter to test a length of wires and gives a beep when there is a connection made between both ends, no beep means there is a break in the wire. This has several applications to repair and test. Lets give one such use a try in our PC:

1. Get a good power supply cable and one that you know to be faulty.
2. Select the continuity setting on the INNOVA 3320 Multimeter ( Also works on other Multimeter brands and models) 

Select the Continuity setting as seen in the picture
 3. Remove the safety caps from the metallic testing probes on the Multimeter:
Remove both negative (Black) and Positive (Red) testing probes caps 
4. Connect any probe to either end of the power cable. There will be three holes and three prongs on the power cable that match up on either end, be sure to connect the probes at each end to the matching point at the other end.

Connect the probe to the matching end of each prong on either side.
 5. When there is continuity on both ends the Multimeter will beep continuously while the meter touches both ends. This indicates there is a unbroken connection and power can flow freely between both ends. Be sure to test all three Prongs on the power cable, for a bad cable there will be no continuity beep heard this will indicate that the cable is bad and needs changing.
This test has many other application in repairs such as testing the continuity on a soldering job to ensure the connection is clean and many other uses when one needs to know if two connecting points is broken in a circuit.

Test#2:Battery Test.

This test is a fun test and one of my all-time favorites that will have you all over the house and checking the voltage of your batteries, especially if you have rechargeable batteries. This test is ideal in testing any battery to find out if its healthy or almost fully drained and will need a recharge or replacement.

1. Collect the Batteries or Cell you wish to test (Two cells make a battery) take note of the voltage that the manufacturer rates the cell e.g. 1.2 Volts and be sure to identify the positive and negative poles of the battery they are written on the cell.
1.2 Volt Duracell rechargeable battery.

2. Set the Multimeter to the Battery load test and set it to a voltage closest to the voltage of the battery being tested. For my case I have a 1.2 volt battery and the meter is set to the 1.5 V setting.

Select battery load test 1.5 V
 3. Connect the Positive probe (Red) to the positive terminal of the battery and the negative terminal (Black) to the negative terminal.

Connect the battery (Cell)  as seen above.
4. On the display of the device you should see the charge of the battery, weaker batteries will have a weaker voltage compared to the charge written on the Battery or cell.

That's it in the above case the battery is well charged and does not need to be charged or changed. a very week reading would indicate the battery needs to be change or that the battery is dead. There are many application to using this in computers and gadgets, this could be used to test the CMOS battery of your motherboard among other useful uses.

Test#3: The AC Voltage test

I recently had to draw for my trusted Multimeter as there was some power issues around the house and my PC would shut down whenever the TV and the Gaming rig were on at the same time. I used the AC test on My meter to Check my outlets to see if they were delivering enough Juice, I soon realized the electricity was fluctuating and decided to wait it out a bit to see if it would settle down. As expected the power was back to normal in about 2 hours now had I panicked or not had a meter I would be paying the electrician for a wasted trip.

So how do you test your outlets at home to see that the correct voltage is flowing through your sockets, simple:
Step 1: Get your trusted Multimeter and place it in the ACV mode.

Put Multimeter in ACV Mode as seen the Pic.
 Step 2: Place both positive and negative terminals into the wall unit making sure they make firm contact, negative and positive do not matter.
Place Multimeter terminals into the wall outlet one above the other Positive or negative order do not matter. 

You should get a reading that's very close to the Voltage of your house

Step 3: Read the display, if your house is wired with a 120 voltage you should see a number very close to the 120 volts, my reading was 117.6 Volts and that tells me the outlet is giving the correct voltage. This can be used to tell when a outlet is faulty or if you have a wiring fault in your house, this could save valuable time and money. This test can also be applied in a number of other ways as well.

OK readers so what cool things are you doing with your spanking new multimeter? be sure to leave your comments or a question.

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