Conference 7.286::home_work

    I have a Sears DVM for $49.00 that has auto-ranging. I noted that
    Heathkit is marketing a pocket type DVM with auto-ranging for $24.95.
    The auto ranging allows the DVM to pick its own range. The only
    thing you have to change is between ohms/AC/DC ranges. The device
    runs on two AAA 1.5 volt batteries.
    
    /cal hoe

    Jeff,
    
    I just looked at the Analog multimeters in my Radio Shack catalog.
    They have four models with an analog meter, but only one goes up
    to an amp or more for current measurements. That one sells for $49.95
    and will measure up to 10 amps. The next best one is $29.95 and
    will go up to 300 milliamps DC.
    
    The lowest priced DMM (Digital Multimeter) they carry which will
    measure at least an amp of current goes for $49.95.
    
    For general use around the house for continuity, voltage and current,
    I like an analog meter (just a personal preference)
    
    My Lafayette meter which I got in 1968 for about twelve bucks is still
    going strong and I think I've only changed the battery once or twice.
    
    Jim

    re. .2
    I also find that analog meters are better for almost all household
    (and even non-precision industrial) uses.  The trouble with DVM
    is that you cannot as easily see a change in voltage, resistance, and
    current.  Using a DVM, it is more difficult to notice numbers changing
    in value than the swing of a needle.  This is especially troublesome
    when "ringing out" cables with an ohmmeter (where you have the luxury
    of having a person on the other end of the circuit tapping the
    individual wires to ground - on a dead circuit of course!).  I also
    find that a DVM is so sensitive that when induced voltages appear
    on a wire, you mistaken assume they are hot.  A lower sensitivity
    VOM will quite readily show these voltages as being induced because
    you can switch downward to the next lower range and find that there
    is a drop off in voltage due to the circuit loading of the meter.
    You will not damage the meter if you always start on the highest
    scale and if you momentarily switch to a lower scale and then back
    again.  Of course, DON'T PUT THE METER IN OHMS WHILE MEASURING LIVE
    CIRCUITS.  That goes for the ammeter scale as well.  
    
    I also find that the needle type probes are a hazard because they
    can carry large amounts of current and are easy to short to ground
    when measuring voltage.  The easy hooks carry less current and are
    shorter and safer - for voltage and current measurements.  This
    experience is from a bitter industrial episode.
    
    Just two more short safety items:  When taking measurements, try
    not to hold the meter close to your face when energizing the circuit
    or touching with the probes - meters sometimes fail internally and 
    explode.  Don't try to measure more than 440 volts - those VOMs
    and DVMs really aren't insulated for higher voltages even though
    they have ranges that often go to 1000 volts.  If you must measure
    such circuits, set up the meter and stand away somewhere and switch
    on the power.

    If you want to measure larger amounts of current safely with a smaller
    meter, get a shunt and put that in the circuit and measure the
    millivolt drop across that.

The meter that used to be sold at Radio Shack for about $40 and went on sale 
for $20-25 is the one I have.  That has been a good performer since the 
mid 70s and has been sold by RS until very recently.  It may still be 
in some RS stores (and is probably listed in last year's catalog.)
I believe that Sears also sells that model under a different name.

By the way, I recently got the Clamp-on AC Ammeter/voltmeter from Radio
Shack (22-161) and have been very happy with that.  (They have added a
voltmeter scale to the model sold last year--I got it on a raincheck
because they ran out of last year's model during the sale.)  If you are
interested in AC current, this unit has the specific advantage of
offering both the clamp mode (where you can isolate a black wire to
clamp around) and a plug/socket arrangement into which you can plug an
appliance and measure its current drain (also has x10 multiplier). 

Alex

    For those that want to spend a little more money, think they can
    really use a DVM, but do not want to give up an analog movement
    for things like relative changes or nulling, some DVMs (like my
    low-end Fluke) have an LCD bar scale underneath the digits for
    analog-like measurements.  The Fluke starts at $79.95, I believe.
    
    __Rich

RE: .5

The Sears version of my multimeter has just gone on catalog sale.  It is
pictured on the second or third page of the new hardware catalog sale
brochure and is about $20 (half of the normal price).  Recommended. It
even has a range doubler feature. (And if you don't like it, return it
to Sears and you'll even get the shipping charges refunded.) 

Alex

    I have a cheap SW PERRY meter/tester. It contains a 1/10 amp glass
    fuse. I guess I blew it when I was testing the transformer for the
    lighting in my daughters doll house. Not being an electrical genius 
    I must have used the wrong scale. 
    
    Now, where do I get a replacement fuse, locally.
    
    
    Steve 
    

    Try Radio Hack (I mean Shaft, ooops, that's SHACK).  They
    MAY have fuses that small.
    
    Uh, where's "locally", anyway?  If you're in northern Mass
    you can also try Active Electronics in Woburn.