G
greenwanderer108
In my electronics enlightenment journey, I find myself indulging into th
fundamentals of understanding the basics of circuits---starting wit
understanding DMM readings.
I want to make sure I have the fundamentals first before I blow any fuse
or circuits from making simple measurements.
Surfing the various threads regarding the Digital Multimeter, I understan
that Volts must be measured in paralell with the black lead (com) on th
negative and the read lead (Volt 200mA max)
And amps must be measured in series with the actual current runnin
through using blac (com) and red (either 10 ADC 10 amp max unfused or th
Volt-ohm 200 mA max fused)
As far as measuring VDC. With the DMM set to 20 DCV, I measured som
fairly new batteries (one 9v and 6 1.5volt AA size in series = 9volt)bu
for both of these the readings showed less than 9v...aprox 8.3 - 8.
volts. Then I tested an old 9volt battery that couldn't even power th
DMM. This gave a reading of a little more than 4 volts. So why do voltage
vary. I understand that batteries are depleted of amp/hours, etc., bu
wasn't aware that it applied to voltage. Can someone put light to thes
observations...
Now, the tricky part... Measuring amps. I haven't yet gotten to the leve
of measuring individual components, resistors, transistors, diodes, etc
so no need for the related ambiguous jargon just yet . Anyhow, The scale
confuse me. On my particular model (YUGO DT-830B)the DCA selection is 20
microamps, 2000 micro amps, 20 miliamps, 200 miliamps, and 10 amps.
Does, 10 amps mean that it's the maximum amps it can read, 200 miliamps i
the maximum amperage this selection will take...or??? What if we don't hav
a clue how much amps a certain load draws, let alone how to read the DM
scales.
For example, I hooked up a 3 volt motor with 2 AA batteries. As I don'
have a clue whether a 3 volt motor will draw more than the maximum 200 m
of the one red terminal, I assume it was better to use the 10 amp ma
unfused red terminal. So the positive terminal from the battery with th
red lead, and the black lead in series on to the load (motor).
All kinds of varying readings jumping around. And I'm not sure how t
interpret them. With the DMM set to 10A, I get average readings betwee
.09 all the way up to .25 Then with it set to 200 m, the readings ar
between 1.1 to 2.8.
So how do I interpret these into amps/miliamps? The assumption is tha
such a small motor can't possibly be drawing 1 or 2 amps, well, I don'
really know. That's why I'm posting.
So on top of interpreting the confusing scales of amps, also I would lik
to know why I can't get a steady still reading of volts or amps with th
running motor.
Also, is it possible to measure amp hours of battery cells with the DMM
If so, how must one proceed?
Thanks in advance.
This message was sent using the sci.electronics.basics web interface o
www.Electronics-Related.com
fundamentals of understanding the basics of circuits---starting wit
understanding DMM readings.
I want to make sure I have the fundamentals first before I blow any fuse
or circuits from making simple measurements.
Surfing the various threads regarding the Digital Multimeter, I understan
that Volts must be measured in paralell with the black lead (com) on th
negative and the read lead (Volt 200mA max)
And amps must be measured in series with the actual current runnin
through using blac (com) and red (either 10 ADC 10 amp max unfused or th
Volt-ohm 200 mA max fused)
As far as measuring VDC. With the DMM set to 20 DCV, I measured som
fairly new batteries (one 9v and 6 1.5volt AA size in series = 9volt)bu
for both of these the readings showed less than 9v...aprox 8.3 - 8.
volts. Then I tested an old 9volt battery that couldn't even power th
DMM. This gave a reading of a little more than 4 volts. So why do voltage
vary. I understand that batteries are depleted of amp/hours, etc., bu
wasn't aware that it applied to voltage. Can someone put light to thes
observations...
Now, the tricky part... Measuring amps. I haven't yet gotten to the leve
of measuring individual components, resistors, transistors, diodes, etc
so no need for the related ambiguous jargon just yet . Anyhow, The scale
confuse me. On my particular model (YUGO DT-830B)the DCA selection is 20
microamps, 2000 micro amps, 20 miliamps, 200 miliamps, and 10 amps.
Does, 10 amps mean that it's the maximum amps it can read, 200 miliamps i
the maximum amperage this selection will take...or??? What if we don't hav
a clue how much amps a certain load draws, let alone how to read the DM
scales.
For example, I hooked up a 3 volt motor with 2 AA batteries. As I don'
have a clue whether a 3 volt motor will draw more than the maximum 200 m
of the one red terminal, I assume it was better to use the 10 amp ma
unfused red terminal. So the positive terminal from the battery with th
red lead, and the black lead in series on to the load (motor).
All kinds of varying readings jumping around. And I'm not sure how t
interpret them. With the DMM set to 10A, I get average readings betwee
.09 all the way up to .25 Then with it set to 200 m, the readings ar
between 1.1 to 2.8.
So how do I interpret these into amps/miliamps? The assumption is tha
such a small motor can't possibly be drawing 1 or 2 amps, well, I don'
really know. That's why I'm posting.
So on top of interpreting the confusing scales of amps, also I would lik
to know why I can't get a steady still reading of volts or amps with th
running motor.
Also, is it possible to measure amp hours of battery cells with the DMM
If so, how must one proceed?
Thanks in advance.
This message was sent using the sci.electronics.basics web interface o
www.Electronics-Related.com