Essential Question: How can I test whether electricity is coming out of the wall?
Mastery Objectives:
Learn how to test electronic devices to make sure they are working.
Learn how to test batteries to see if they have power.
Learn how to test an outlet to see if electricity is coming out of the wall.
Directions: Create a presentation of pictures of yourself testing speakers, an AC adapter, a Power Source, a battery, and a CMOS battery. Put the measurement into each slide below the image. You are doing this assignment individually but you can work with a partner to help you take the image. Here are the steps for testing the different devices. Make sure that you are careful and read the directions.
Testing Speakers
Set multimeter to 1,000 ohms
Cross the red and black prongs together to test to see if the multimeter works. The multimeter should move to 0. The only time you cross the prongs is when the multimeter is set to ohms.
If the multimeter moves when you touch the red and black prongs together but the setting is not on 0, adjust the multimeter so that it read 0 using the ohm adjustment dial.
You can only touch the prongs together when testing conductivity using ohms. Never cross them when the multimeter is set to volts.
Put the black cable (ground cable) (when testing conductivity it is called the common cable) closest to the top of the end that gets inserted into the computer.
Put the red cable at the different channels (middle and bottom of the end that gets inserted into the computer.
If it is working, the ohmmeter should go to 0.
Testing AC adapter
AC adapter must be plugged in
Set multimeter to AC Volts in the range closest to the range specified on the outside of the AC adapter. The AC adapter usually has a sticker on the outside of it that specifies voltage. Sometimes it is DC but usually it is AC. Look for the output section. If it says 9DCV – then change the multimeter to DC.
Take the black cable and put it on the outside of the end of the cord. This is the common area.
Take the red cable and stick it into the hole of the cord. This is the hot area.
If the AC adapter works, then there will be a change in the multimeter.
Testing Power Source - https://www.youtube.com/watch?v=6Su29IUYA5U
Set multimeter to AC Volts close to the 120 Volts range
Put the ground cable, or black cable into the larger slot of the three-prong outlet
Put the hot cable, or the red cable into the smaller slot of the three-prong outlet
The multimeter should go somewhere in the 115 V – 120 V range
If you get a voltage other than 120 V, why?
Testing Batteries
Set multimeter to DC volts close to the voltage of the battery
Put the ground cable, or black cable touching the negative side – no bump has - symbol
Put the hot cable, or red cable touching the positive side – bump on the end has + symbol
You should receive the same voltage as the battery if the battery still has power
Testing CMOS Batteries
If the CMOS battery is in the computer, then shut computer off completely, unplug computer, put wristrap on,
Unlodge the CMOS battery by using a flat-head screwdriver, do this gently
Use a Multimeter to test the battery
The positive side of the CMOS battery will have a plus sign “+”. Place the red lead on the positive side
The negative side of the CMOS battery will have a negative sign “-“. Place the black lead on the positive side
Set the multimater to DC volts at the lowest number
The voltage should read around 3. If the voltage is lower than 2.5, then consider replacing the battery. If the voltage is lower than 1.8 volts, then replace the CMOS battery.