tag:blogger.com,1999:blog-5088860151651047897.post7540843591373894770..comments2024-03-25T10:56:59.380-04:00Comments on Jacobs Physics: Finding an appropriate digital multimeterGreg Jacobshttp://www.blogger.com/profile/03854009948036330746noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-5088860151651047897.post-40395374222750198142012-10-18T11:31:54.100-04:002012-10-18T11:31:54.100-04:00I'm just teaching Junior High kids... What'...I'm just teaching Junior High kids... What's the simplist and most reliable meter to get to show conductivity?<br />emillerhttps://www.blogger.com/profile/04022336758719223349noreply@blogger.comtag:blogger.com,1999:blog-5088860151651047897.post-56186838138352559432011-02-05T17:04:34.841-05:002011-02-05T17:04:34.841-05:00For student labs, I actually prefer analog meters:...For student labs, I actually prefer analog meters: ammeters and voltmeters. "Old school," with needles! I also prefer power resistors (3-ohm, 5-ohm, 8-ohm, 10-ohm for example, rated at 10 watts or so.) And I like to use well-regulated, 0-6 V variable DC power supplies.<br /><br />Together, they allow for an Ohm's law lab whose data is rife with values between 0-10. Easy numbers to deal with when the concepts are difficult enough.<br /><br />All those things cost money. But amortized out across 100+ students over 10 years, it's pennies per kid. Cheap analog meters might not last ten years in the lab, but good power supplies will, and the power resistors (though ceramic) are sturdy enough.<br /><br />It's rare for a student to hurt a meter in my class (unless they knock it off the table). I like a needle lunging the wrong way to tell them they need to reverse the connections. And I like the sweep of the deflection indicating more or less current or voltage.<br /><br />I actually skip past DMMs and use a current/voltage sensor for the AP (second-year) Ohm's law and resistivity labs. We also use those sensors for our capacitor labs, where they generate nice charging and discharging graphs.<br /><br />I guess I was just never a big fan of multimeters in the classroom. But that's one more reason why Baskin-Robbind makes 31 flavors.Dean Bairdhttps://www.blogger.com/profile/17681829220589441713noreply@blogger.com