Multimeter functioning [newbie question]

Neutron wrote:

To get familiarized with your new mmeter, you could try using it on known sources first. Try testing a 9V battery on the DC 20 volts range. I see by looking at the picture that the ranges are not labeled "DC" "AC" etc. The upper right quadrant is DC volts (symbol is a solid bar over a dotted line to indicate you are measuring some voltage on one side of zero volts). The reading will be close to 9 volts for a good battery. Try using the AC volts range (lower right quadrant -- symbol is a sideways "S" to indicate you are measuring a voltage that alternates between positive and negative in a regular cycle) to test a wall socket (110 to 120 volts). Shorting the leads together on the ohms scale (upper left, with the Greek letter omega -- the symbol for ohms) should give you a reading o zero (if not, there is usually a trim control to adjust for zero). The lower left quadrant ("A") is the amps range. This is used to measure current by placing the meter leads in series with the circuit. Use this range with caution (wait until you have more experience with the meter). In all cases, make sure the meter is in a high enough range to avoid an over range reading. In other words, choose a range that is bigger than the voltage you expect to read. When testing an unknown, start at the highest range and work down ranges if needed. ALWAYS MAKE SURE YOU ARE IN THE CORRECT RANGE, OR YOU MAY DAMAGE YOUR METER. Also, remember the one cardinal rule of multimeters -- NEVER MEASURE VOLTAGES ON THE OHMS SCALE. Have fun!

Nels Remember -- All things run on smoke If you let the smoke out, it won't work anymore.

One additional note -- The 110-120 volts AC I spoke of above is the standard in the U.S. I see you ordered from a NZ company. Does this mean you are not in the U.S.? If so, your wall socket voltages may be different (higher). Set your range accordingly. That "world wide" thing caught me again.

Nels

Was there no manual?

The "->|-" I bet looks like the common diode symbol, and is there for checking the junctions of diodes and other semiconductors. It's a variant of the ohmmeter function, in that it applies small voltage to the probes so you can measure resistance. But it is arranged so it can better check those semiconductor junctions. Put a diode across the leads, and set the function switch to that function, and in one direction you will get a maximum reading (ie the same as if nothing is connected to the leads) and in the other direction you will get a low reading. That's for a good diode. A shorted one will show a low reading in both directions, an open diode will show a high reading in either direction. The reading you see if it's a good diode will let you determine the type of diode (ie germanium which you aren't likely to come across much, silicon and schottky, since each have a different voltage drop). Since a transistor is two junctions, you can use the function to check the junctions of those, though you'll have to check the base-emitter junction, and then the base-collector junction.

The "HFE" is for measuring transistor gain. There should be a socket to plug the transistor into for doing the measuring. I've had a meter with the function for almost ten years, and other than playing with the function at the beginning, have never used it.

Michael

I'd say "unfortunately" for you! You learn a *lot* more when something doesn't work and you have to debug it!

There are on-line tutorials like these:

Books abound as well, visit your local library or uni library.

Dave :)

numbers

Thanks for all your help !!!! :-)

Yeah there was a warning on the (lacking) instructions about measuring that sort of thing. There's also a "hFE" setting on the bottom as well on the lower right qudrant, and another setting that looks like this "->|-" (sorta). Could you suggest what these might be for ?

Cheers.

go

process.

Actually, I do have to adjust the voltage on T2 and T4 so this will assist ! (It's a theremin kit BTW)

You got some good answers about how to use your meter. Beyond that, I would suggest you look up Ohm's law and the other laws that relate current, voltage, resistance, and power. You will understand much better what those measurements you get with your meter really mean.

That's for testing transistors and seeing how well they work, for that use use the small round socket labeled E C B E PNP NPN etc

the ->|- symbol the diode symbol it'll measure the forwards voltage drop. it'll give you a reading og 0.6 (approx) for a silicon diode and abour 0.2 for a germanium diode.

always remember to turn it off bacase the cheap DSE multimeters don't power down automatically and so will run the battery down if left on overnight a few times.

get a few spare fuuses for it cause it's pretty easy to blow them if you mis- use it on the mA scale. (there is room inside the case to store them if you wrap them in plastic)

Bye. Jasen

That was your first kit, and it works? well done!

(I'm assuming it was either the Jaycar or the Altronics version of the Aug

Bye. Jasen