Well i JUST got a brand new DMM at canadian tire for 15$ and it should be good enough for my purposes.
I was wondering how you can measure your ams output? p=I*V i know that much, but what setting do i use to measure voltage? it keeps reading zero, i have the red plugged into the 10A max and the black into the com.
Also, when an amp increases its power output, what increases? current? or voltage? or both?
I was wondering how you can measure your ams output? p=I*V i know that much, but what setting do i use to measure voltage? it keeps reading zero, i have the red plugged into the 10A max and the black into the com.
Also, when an amp increases its power output, what increases? current? or voltage? or both?
Trying to measure max power output with a speaker connected is difficult and probably not too smart. You could damage your amp and/or speaker, not to mention your meter.
Pros measure the sine wave voltage output at clipping as viewed on an oscilloscope into a test load of 8 or 4 ohms. Volts = amps * ohms and Power = Volts^2/Ohms
Read the manual about how to measure voltage - I think you have the leads on the wrong input. Your $15 DMM will not have flat response below 40Hz or above 1000Hz - it is calibrated for 50-60Hz sine waves only. You can't measure with music signals and since you don't seem to know how to use a DMM I suggest you be very careful or you will blow up your new toys.....
Pros measure the sine wave voltage output at clipping as viewed on an oscilloscope into a test load of 8 or 4 ohms. Volts = amps * ohms and Power = Volts^2/Ohms
Read the manual about how to measure voltage - I think you have the leads on the wrong input. Your $15 DMM will not have flat response below 40Hz or above 1000Hz - it is calibrated for 50-60Hz sine waves only. You can't measure with music signals and since you don't seem to know how to use a DMM I suggest you be very careful or you will blow up your new toys.....
"Also, when an amp increases its power output, what increases? current? or voltage? or both?" -- both. When impedance is held constant and voltage increases, current increases due to Ohm's Law (V=IR or in this case, V=IZ)
You can measure power output with a DMM but to measure MAX power output, I agree, you need an oscilloscope to see when it starts to clip.
You can measure power output with a DMM but to measure MAX power output, I agree, you need an oscilloscope to see when it starts to clip.
well thanks guys! i might have made a serious mistake(and *gasp* ended up one toy short :O)!
I know my friend blew his dads DMM up testing wall outlets (usually 15 amps no? and the meter sais 10 amp max?)🙄
Also another question (im starting to wish i had a couple DIY fanatics on msn for quick questions haha)
How would i measure the FS of a certain driver? i have a disc with pink noise, white noise, test tones, and i have my brand new trusty DMM 😀
I know my friend blew his dads DMM up testing wall outlets (usually 15 amps no? and the meter sais 10 amp max?)🙄
Also another question (im starting to wish i had a couple DIY fanatics on msn for quick questions haha)
How would i measure the FS of a certain driver? i have a disc with pink noise, white noise, test tones, and i have my brand new trusty DMM 😀
You NEVER measure current in parallel. You have to break a circuit to insert an ammeter. Only voltage may be measured by plugging the leads into the wall socket.
But decent DMMs are available for cheap on Ebay.
But decent DMMs are available for cheap on Ebay.
Only insert CAT rated meters into wall sockets, otherwise they are dangerous and some one could get hurt by HV spikes
www.diysubwoofers.org
Usually there's 4 imputs on a DMM.
10A, 100mA, Comm, Voltage
To measure small current, you use the multimeter in series with the speaker, same thing with large current. You plug the output of the amp on one wire of the multimeter, the other wire on the multimeter go to one speaker wire speaker, and the other speaker wire coming back from the speaker to the amp to close the loop.
Safer to use the 10A when using speakers because you'll blow the fuse and need to replace it if you use the 100mA.
To measure voltage or resistance, you need to use the voltage imput. To measure voltage, you place the multimeter in parallel with the speaker, so you plug one multimeter wire on each amplifier terminal or speaker terminal. You don't need to care about current when measuring voltage, even if a socket can give 15A, a multimeter have a very high resistance when measuring voltage, around 10 MegaOhms, so the current going in is less than 12 microamperes at 120 volts. If you want to measure current, the multimeter would melt and burn and/or the house breaker will cut off the outlet.
To measure resistance, you need to unplug everything and put one multimeter wire at each end of the thing you want to measure resistance.
The other wire is always in the comm imput, you only change one wire and leave the other in the comm imput.
10A, 100mA, Comm, Voltage
To measure small current, you use the multimeter in series with the speaker, same thing with large current. You plug the output of the amp on one wire of the multimeter, the other wire on the multimeter go to one speaker wire speaker, and the other speaker wire coming back from the speaker to the amp to close the loop.
Safer to use the 10A when using speakers because you'll blow the fuse and need to replace it if you use the 100mA.
To measure voltage or resistance, you need to use the voltage imput. To measure voltage, you place the multimeter in parallel with the speaker, so you plug one multimeter wire on each amplifier terminal or speaker terminal. You don't need to care about current when measuring voltage, even if a socket can give 15A, a multimeter have a very high resistance when measuring voltage, around 10 MegaOhms, so the current going in is less than 12 microamperes at 120 volts. If you want to measure current, the multimeter would melt and burn and/or the house breaker will cut off the outlet.
To measure resistance, you need to unplug everything and put one multimeter wire at each end of the thing you want to measure resistance.
The other wire is always in the comm imput, you only change one wire and leave the other in the comm imput.
Thank you very much for covering everything the manual didnt!
However my multimeter only has a com a 200ma/voltave/ohm and a 10A max input, but that shouldnt matter( i can apply your instructions to my multimeter).
I also never knew that you didnt have to pay attention to current when measuring voltage! that makes the cause of my friends multimeters death a mystery :S
However my multimeter only has a com a 200ma/voltave/ohm and a 10A max input, but that shouldnt matter( i can apply your instructions to my multimeter).
I also never knew that you didnt have to pay attention to current when measuring voltage! that makes the cause of my friends multimeters death a mystery :S
If he tried to measure the current, he could have killed his multimeter. But if he measured the voltage correctly, no problems.
If the wire is in the 10A imput and you want to check the voltage of the wall socket, when you see your mistake that it's not in the right imput, you probably already killed the multimeter, because the 10A imput have very very low resistance (under 1 ohms) so you're burning up the circuit board! 😀 It's like if you drived your multimeter with 1800W RMS into 1 ohms car amplifier...
When the multimeter is set to voltage mode and the wire is in the right imput, you can usually measure voltage up to 1000V or so. Not recommended unless you know what you're doing.
If the wire is in the 10A imput and you want to check the voltage of the wall socket, when you see your mistake that it's not in the right imput, you probably already killed the multimeter, because the 10A imput have very very low resistance (under 1 ohms) so you're burning up the circuit board! 😀 It's like if you drived your multimeter with 1800W RMS into 1 ohms car amplifier...
When the multimeter is set to voltage mode and the wire is in the right imput, you can usually measure voltage up to 1000V or so. Not recommended unless you know what you're doing.
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