The dangers of digital multimeters and what to do about it are some of the things that shouldn't be done with them.

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I scored a free analog multimeter by buying and installing a new fuse, and now it works like a charm.The rating of the new fuse is the same as the blown one I found inside.There is a triangle with an exclamation point inside the meter that says 500V.

I am a Computer Science student, so I'm completely new to electrical engineering.My question is, besides accidentally passing the or k settings while hooked up to a power source, what other things should I avoid doing to prevent the fuse blowing or any other damage to the meter or myself?

Besides accidentally passing the or k settings while hooked up to a power source, what other things should I avoid doing to prevent the fuse blowing or any other damage to the meter or myself?

The use of AC mains is important.Before considering material in the main section, do not use 220 or 230 VAC mains.

Make every effort to not overload the mA.A low current range (500 mA and less) will usually be fused.This will go open circuit if it is overload by 1A.This can be very annoying.

Chris mentioned something.It's worth repeating.There are two hard wired leads on some meters.There are two probe sockets in some meters.There are 3 probe sockets in many meters.The high current positive can sometimes be shared by other functions.A high current positive input allows a very low resistance unswitched shunt to be used for current measurement of 10A or higher.The shunt will be present from common to high current +ve if the meter is set to that.If you attempt to measure the mains voltages by setting the meter to AC volts, the shunt will be placed across the high voltage source.This can be very exciting.It's something you really don't want to do as there is usually no fuse in this arrangement.I've lived and done it.The shunt may live if it has more hair on it's chest than on its mains.Subsequent to that, your calibration may vary.

Some meters have low voltage ranges, some have 200 mV and a few have 20mV.The basic digital meter IC may be used with the low current ranges.Don't apply high voltages.

If you have a low ohms range, be sure to short the probes together before measuring to determine the zero point - this is at least the lead resistance plus any contact resistance in the problem plugs and sockets.Zero resistance can be reduced and Stabilized by twisting the plugs to and from.

The apparent resolution and repeatability of most meters is higher than the accuracy.DC accuracies can be 1% or 2% and AC may be 5% or worse.

Some meters have a low battery indicator.Some don't.When the battery voltage is too low, some meters get very inaccurate.Some are stable.You need to be aware of effects and state of battery if your meter doesn't have a low battery indicator.If the meter is an especially useful one, you can check it's accuracy every time you use it.It may be worth not using a meter that fails under low battery if it has no warning or warning at all.

The Imeasured x Rmeter current drop is the result of the current range resistance being measured.Most meters have a resistance of 1 Ohm or less so that at 200 mA the meter drops 0.2V.This is usually low enough to not be very important and can usually be allowed for.I have a meter that has 17 Ohms resistance on the 200 mA range, meaning that it drops a massive 3.4 Volts across the meter.The "designer" of the meter needs a severe talking to before or after tar and feathering.In a situation where many people may use the meter, it may be best to discard it..

If you value your life, you must have a meter that is better rated than the one you have now.

It's a good idea to use machines that are Cat II or higher on AC mains.Many lower cost meters are not rated.

AC mains should be used with caution.Both are lethal on 230 VAC rayher.If mains is the main's peak, it is 230 x 1.414 (sine wave RMS to peak factor).500 V is more than 50% above this but spikes and Murphy can make meters not specifically rated for 230 VAC operation erupt in colourful smoke and flames.It's rare that people also die when the meter does.This can happen if the meter draws anarc from a high energy source and the meters don't interrupt it.If the fuses don't get in the way, the household mains supplies can be up to 100A.

When the initial current surge vastly exceeds their rated fusing capacity, test equipment designed for use with high voltage high energy sources will use HRC fuses which are able to blow and stay blown.

If the equipment is not designed to break such an arcs, using an HRC fuse is pointless.Most cheap meters don't have this capability.

If a meter fails under high voltage break down, there will be a pleasant sound from within, smoke from various orifices and a bad smell.The user won't be directly affected.If the meters are used on the AC mains, please pray for high values.

If the source is able to sustain a very high current, a meter and fuse not rated to break such a current may allow an arcs to form and sustain across the meter.People have died when using an unsuitable meter.

If you want to measure current you can connect the amperemeter to the circuit where the current is to be measured.For an idea of how that happens, see this question.

It looks like the extreme of that.A person with a PhD in physics grabs a multimeter and thinks "Oh, let's measure the current in the mains outlet"The probes are put into the outlet to cause the circuit breakers to trip.I have no idea why the meter didn't blow.

What happens here?An amperemeter has very low resistance, so connecting it in parallel to the circuit in which a current is to be measured shorts that circuit and also the power source that powers it, since they are connected to each other.This could result in very high currents and could cause the meter to blow.

I was playing with a flyback transformer and connecting a 9V battery to it's primary, but the multimeter was dead and I didn't have the right timing with the battery.

This doesn't apply to this multimeter in particular, but it's a good idea to know the voltage rating for each range you have on the multi meter.

For example, if I have a multimeter that does frequency measurement, the maximum voltage is 60 V.

Recent personal experience reinforces things mentioned.I tried to test for a drain on my car battery by putting the multimeter in series with the circuit while the car was turned off and doors and lights were not on.I left the positive probe plugged into 200mA MAX because I was very cautious.The meter stopped displaying values after I got a reading for about a quarter of a second.The blue genie smoke was released by several components after I took it apart.I have been trying to get the smoke out.

I let go of some alligator clips that I was using at the time and they touched the positive and negative posts of the voltmeter and it never worked again.I just got it as well.