Multimeters                      

Every electronician uses multimeters. And some electronicians develop a fetish for multimeters, collecting many of them.  For most of my life I have only procured the multimeters I really needed, which were very few, but lately I have been adding some more, so I decided to write this page in order to let other people see why I selected which meter, what's good and what's bad about them, and specially to help others decide what features to look for when shopping for multimeters.

Multimeters come in two big classes: Analog and digital. Each of these have their own set of strengths and weaknesses, so it's a very good idea to own at least one of each type. Analog meters excel in measuring variable, unstable signals. The meter will simply show the average of fast varying signals, or follow slowly varying ones, while digital meters will give almost unreadable, unstable sequences of numbers. On the other hand, digital meters are enormously more accurate and resolving, and also can take more abuse, like being dropped on the floor, or putting 500 volts into them while set to measure resistance. This does happen even in the best families...

But then, many digital meters are big liars: Under some specific conditions, they might give totally wrong output, due to saturation effects, RF pickup, or whatever. Analog meters instead are dumb and honest. Not very accurate, but they won't really lie.
 
Most analog meters are very simple affairs: Just a highly sensitive galvanometer, along with a set of dividing resistors and a switch to select them, to achieve the different ranges. Their batteries are used just to provide a power source for measuring resistance, continuity, diodes, etc, but aren't needed for measuring voltage and current. Most of the time these meters draw no power at all, and can be left on indefinitely.

Some analog meters include a high input impedance amplifier. In ancient times these were called "vacuum tube voltmeters", while more modern ones use FETs. Some advanced analog meters have autoranging functionality, but those aren't very common.

Digital meters come in two main flavors: Manual ranging and autoranging. Some electronicians have a strong preference for one or the other type. The fact is that each type has specific advantages: Convenience for the autoranging ones, speed for the manual ones, because they don't have to determine the proper range for every measurement. My opinion on this matter: Since almost all autoranging meters can be switched into manual ranging mode, I prefer autoranging meters, which give me both systems in a single meter. So I can use what best suits each measurement situation.
 
Simple digital multimeters often have the same basic structure as an analog meter: A bunch of ranging resistors and a range/function selector, combined with a basic instrument. Only that this basic instrument, instead of being a galvanometer, is a single-chip digital voltmeter. Old meters very often used the ICL7106 chip. Autoranging meters often have a purpose-designed chip, that has all functions built in. A later trend is to build multimeters around standard microcontrollers, like a PIC or Atmel. These can have many clever additional functions, but often suffer from excessively high current drain, and designers tend to build tricky software into them that can sometimes fool the user.

Now let's round up all multimeters I have owned in my life! I will describe them in the order I got them.

Kaise 242

I got this meter by special request from Santa Claus, at a rather tender age (at least for an electronician), when Christmas was still a good excuse to get much-needed things otherwise unobtainable. It served me very well for several years. Since film for my camera also had to be obtained from Santa Claus, and was scarce, I never shot a photo of the meter by itself, and you have to satisfy your curiosity with this photo, that shows the meter along with a completed lab power supply, 40 meter DSB QRP transceiver, SWR meter, plus a bare bones 30 watt linear amplifier and antenna tuner, all of them built with no other measuring instrument than this multimeter.

This was a plain, simple, inexpensive multimeter of its time, the late 1970's. I think it was made in Taiwan, and the brand and model number are purely from memory, so I hope I got that right! The meter measured AC and DC voltage, resistance, and current up to 250mA, if my memory doesn't kid me. In addition to the main two probe terminals, it had a capacitor-coupled terminal, used to measure the AC component of a signal while stripping the DC.

This meter was a 20 kΩ/V instrument. Modern electronicians might need an explanation about this. Basically, when measuring DC voltage, such a meter was simply a sensitive galvanometer in series with a total resistance selected accoring to the range. For example, the galvanometer might give full scale deflection with 50A flowing through its coil. So, for any desired voltage range, enough resistance was connected in series to make 50A flow when the full-range voltage was applied. The total input resistance would then be 200kΩ in the 10V range, 20MΩ in the 1000V range, and so on. Hence that kΩ/V rating. 20kΩ/V was average. Good meters had more, up to 100kΩ/V for the best, while the cheapest meters might have just 5kΩ/V or even less. This was for DC voltage. The AC voltage kΩ/V rating was always lower.
 
This multimeter had a single AA battery inside, for the resistance ranges.
  
It served for several years, but then the meter movement started becoming sticky, due to wear. Several times I opened it up and tried to clean the movement, adjust its clearance, but things kept getting worse, until the Kaise had to be retired from active duty. Anyway over that time I had blown up resistors in it on several occasions, by forgetting to set it to the proper range before measuring some voltage. These analog meters weren't forgiving of such mistakes. Since 1% accurate resistors were unobtainable where I lived, I replace the burned resistors by selected 5% ones, using combinations in series or parallel to keep a decent accuracy. When the meter movement finally got too worn for continued use, I declared the meter dead, and obtained a new one. Eventually I threw away the carcass of the Kaise, the only one to suffer that sad fate. I still keep all my other multimeters, in good operating condition.

Philips ST-505

This is a better quality analog meter. It has a 50kΩ/V rating, thanks to a very sensitive meter movement with sapphire bearings, and it also has some degree of built-in protection. It has a 10A current range too, which I missed on the old meter. It uses two AA cells to power the resistance measurement, and the full 3V are available at the test probes, so that the meter can even test white LEDs - which didn't exist at all when the meter was made. On the other hand, this high testing voltage makes any semiconductors in circuits conduct, so that it's often not possible to measure the resistance values of resistors connected to a circuit containing semiconductors.

One quirk of this meter, and of many analog multimeters, is that during resistance testing the polarity of the test leads is reversed. The positive lead becomes negative! This must be remembered when using such meters to test diodes, transistors, etc.

It doesn't have any continuity beeper. Few of these old meters did.
 
Since analog meters are unipolar, so that negative input voltages or currents make the meter back up to its left side end stop, a polarity switch is provided on this meter. Of course, reversing the test probes does the same trick, so this switch is never used in practice.

Note the green ohm adjustment wheel. Like most analog meters, this one uses the battery voltage, without any regulation, to measure resistance. This requires joining the test probes and adjusting this wheel for precise full-scale deflection, before making any resistance measurement. When changing resistance ranges, this wheel has to be readjusted, specially between the lowest range and the others, to compensate for the batteries' internal resistance.

Modern safety-minded people might be horrorized by seeing that this multimeter doesn't have full insulation around the test lead connectors. The leads end in simple banana plugs, with lots of exposed metal. So if you connect the leads to a circuit carrying high voltage, and then touch those metal parts of the test lead connectors, you will get shocked. This was plain normal in that time - electronicians were assumed to be bright enough to stay clear of energized connections! Not so today. Today's meters need to be idiot-proof, or they won't get safety approvals.
 
All these quirks were totally usual for such meters, and old-time electronicians know them well, but newer generations might not!

This meter has a mirror arc embedded in the scale. One can adjust the viewing angle such that the needle is in-line with its mirror image, to eliminate the reading error that would otherwise result from a slanted visual line.

When using analog meters, the user needs to understand which scale applies to which range. For example, AC scales are compensated for the non-linearity of the diode used to detect the AC, resistance scales are backwards (zero at the right side), and there is also a dB scale, that allows measuring audio signals directly in dB above or below 1mW on a 600Ω line. Color coding helps in quickly finding the correct scale for each range.

This meter is still in good operating condition, after over 30 years. A few times I blew some resistors, but replaced them. It also fell to the ground a few times, and survived. It went through several big earthquakes, one of those threw it across the room and buried it under lots of other stuff. This cracked the window, but didn't affect its operation.

You may ask why there is an "off" position, when such a meter anyway doesn't draw any battery power? Well, in that position the function switch shorts out the meter movement. This dampens any oscillations of the needle, making the meter movement more resistant to shock during transport.

Yu Fong YF-1220

When I was an university student, in the mid 1980's, I started wanting, or perhaps even needing, greater precision than an analog multimeter can provide. At that time I had a modest income from repairing equipment, so I had gained independence from Santa Claus. But my income wasn't large, so I wanted an inexpensive meter. A Fluke or any other famous brand was out of the question, because of the shamelessly enormous price tags of their products. I wanted the meter to have lots of functions, too. After searching the local stores for some time, I decided to buy this Taiwanese meter made by Yu Fong Electronics. 

This is an autoranging meter having separate resistance, diode and continuity functions, and the special functions included are a battery test with load resistor, and transistor gain measurement. Like most autoranging meters, range selection can be manually overridden. The display range goes from -1999 to +1999, which was pretty much the standard in that time. The rated accuracy is from 0.3% for the best ranges, to a worst case 1.5% for the 10A AC current range. That's better than most cheap meters of its day, and better than many modern ones too.

This meter has some excellent features, and also some nasty ones. Its best feature, which I really love, is its very low power consumption. It runs on two AA cells, which last almost forever! The current drain is slightly under 0.4mA, which should give roughly 5000 hours of operation before the batteries need to be changed. The meter doesn't have an automatic shut-off function, and certainly doesn't need one. I have often forgotten to switch it off, sometimes for weeks, and it just keeps working fine. I replace the batteries once every 5 years or so, just as a prevention against possible leakage, not because they are exhausted!
 
Among the other good features is that this meter rarely does any serious nonsense. It simply works as expected, and its readings are reliable.

Now the bad features: This meter is odd in that one terminal is only for voltage measurement, while another terminal is used for all other functions except the high current range, which is on a third terminal. The negative terminal is the same for all functions. In typical electronic work one is constantly switching between voltage and resistance or continuity measurements, and with this meter that means that one is also constantly moving the positive probe between one receptacle and the other! What's worse is that the Ω/mA/diode/continuity/Bat input isn't protected against any significant voltage, except by a fuse. I can't remember how many times I have blown that fuse! I buy them by the box. In my defense I can say that over the 30 years I have used this meter, my rate of fuse burning has dropped somewhat. But it's stupid to design a multimeter in this way!

Another nasty quirk of this meter stems from the combination of two features. One is that the meter will make a "beep-beep" sound every time it switches the range. And the other is that the meter, like most digital multimeters, has an input impedance of 10 to 11MΩ in all DC voltage ranges except the lowest one (200mV), in which its input impedance is virtually infinite. The result is that in any normal lab environment the meter will pick up some noise and static charges when sitting around with its probes in the air, and then a nasty game begins: Almost immediately the voltage picked up will exceed  200mV, and the meter will switch into the next higher range. BEEP-BEEP! But in that higher range the impedance is only 11MΩ, so the noise and charges picked up are much smaller than 200mV, and the meter switches back into the lowest range. BEEP-BEEP! And then it picks up noise again, and switches up...  BEEP-BEEP!  BEEP-BEEP! BEEP-BEEP! BEEP-BEEP! BEEP-BEEP! BEEP-BEEP! BEEP-BEEP! BEEP-BEEP! BEEP-BEEP! BEEP-BEEP!!!!!!!!!!!  It can make one mad!!!

Shortly after buying it, I disconnected its beeper, to fix that problem. But that means that I lost the continuity beep function, which after all is quite useful. I ended up re-connecting the beeper, but in voltage mode I always use the meter with manual ranging, to stop that irritating recital of beeps. In that way I have used this meter for around 30 years. I had to clean the function switch a few times, I also had to replace the battery holder after it broke due to a very hard landing on a concrete floor, and one time I managed to burn out a resistor, when the fuse wasn't fast enough, and had to replace it. Add a few very slight recalibrations every ten years or so, and this meter is still going strong and is the one I use most. Beep-beep!
  
For diode testing this meter uses about 1.5V open circuit voltage. This was typical in its age, before blue and white LEDs with their higher breakdown voltage were developed. So it cannot test those LEDs. In resistance and continuity modes the open circuit voltage is below 0.5V, so it doesn't make silicon junctions conduct. This is excellent for measuring resistors in-circuit.
 

Mastech MS2102

One constant nuisance with all common multimeters is that any current measurement requires opening the circuit to insert the meter. Also, common multimeters are very limited in the amount of current they can measure - typically 10A, or at most 20A. So any measurement of higher current requires inserting shunt resistors, or possibly current transformers in the case of AC.

Enter the clamp meter: It can measure high currents, without opening the circuit nor inserting anything. For many years I wanted to buy such a clamp meter, but most of the high currents I need to measure are DC, not AC, while most clamp meters only measure AC! The ones that also measure DC used to be prohibitively expensive.

Eventually I came across this Mastech clamp meter. It was the cheapest I found that measures DC too,  and as a bonus it has a pretty good resolution for a clamp meter, 0.01A. It will measure a maximum of 400A, which is modest for a clamp meter, but plenty for my needs. The display covers -3999 to +3999. It has a basic accuracy of 2.5% in DC and 2% in AC, good enough for most purposes.

This meter shouldn't be really called a multimeter. Although it has a voltage function and a combined resistance/continuity function, their performances are so poor that I almost never use them. For example, it measures resistance only up to 400Ω! Everything above that value appears as an open circuit. In voltage mode, it has only two ranges, 400 and 600V, with the best resolution being 0.1V. So, let's consider this thing a current meter with some added "light" voltage and resistance/continuity functionality, but the only part of it that's really useful is the current function. That's what I bought it for, and that's what I use it for. And I'm glad that I have this meter!

It does have some quirks and limitations even for current measurement. One is that in DC it has roughly 0.03A of noise, so that the reading in its lower range (40A) is always somewhat unstable. So, while the rated resolution is 0.01A, in practice it's hard to measure any current to better than 0.03A. Now this has to be seen in the context of clamp meters being high current devices. When measuring tens to hundreds of amperes, 0.03A of noise is irrelevant.

In AC there is less noise, so it works more accurately there.

The autoranging between the 40 and 400A current ranges works well, but manual range selection is available too.
 
The build quality is mediocre. The clamp doesn't always seat in the exact same positions, and requires careful operation to produce reliable readings. The power and function switch developed contact trouble very soon, and required careful cleaning with a de-oxidizing contact cleaner.
 
My biggest complaint is about the battery usage.  This meter runs on two AAA cells, and consumes a whopping 29mA! This means that it sucks the batteries dry in barely 20 hours of use. My usage of the meter is rather intensive, and so I decided to run it on rechargeable cells. Bad luck! The meter won't run correctly on the 2.5V or so provided by two NiMh cells! It needs at least 2.6V to start giving reasonable measurements, and 2.8V to reach full accuracy. But the low battery indicator doesn't come on until the voltage is around 2.3V! It took me quite a while to discover this, and I thought there were contact problems again when the meter gave nonsensical readings despite its battery voltage being OK, according to itself!

So, this meter needs using fresh alkaline AAA cells, and replacing them as soon as the measurements start becoming quirky, such as the zero reference running away, or the meter reading low. The battery condition indicator is useless.

Oh well. It was the cheapest DC-capable clamp meter I could find. Still, it was more expensive than a pretty good non-clamp multimeter having lots of functions. I did expect better quality. Still I'm happy that I got any DC clamp meter at all, and I use it a lot.

Cen-Tech

This is an ultra cheap Chinese manual range multimeter. They come in many slightly different flavors, colors, shapes, and totally different brand names and model designations (if any). I got this one as a gift, from a friend who had gotten several for free, along with his orders for parts. He gave me this one saying that one can never have too many multimeters.

This little cheap thing is actually quite capable and useful. It has one great feature: A power switch that's independent from the function/range selector! It allows switching the meter on and off on the spot, quickly, without disturbing the range setting.

It has the usual DC and AC voltage and current functions, but lacking highly sensitive AC ranges. It measures resistors to 2MΩ, which is modest too, but usable.  It has no continuity beeper. The measuring voltage in most resistance ranges is around 0.6V, so it can partially turn on semiconductor junctions - not very convenient. In diode testing mode, and interestingly also in the lowest resistance range, it uses a 3V measuring voltage. So it can just test white LEDs. It will light them, even if the display keeps showing the overload sign,  given that it shows only up to 1.999V!

The display covers the basic -1999 to +1999 range, and the accuracy of this instrument is anyone's guess - but in almost all practical work it's plenty accurate enough! Even cheap meters like this one are usually within 2%.

This meter has two special functions: Transistor gain, and battery test under load. In this regard it's much like my old Yu Fong. Just a little better in that the battery test function is also usable with 9V batteries.

The meter is powered by a 9V battery, and the current consumption is a reasonable 0.8mA in voltage and current modes. In resistance and diode modes instead it consumes 3.5mA! I suspect it has a simple plain old three-terminal regulator to generate the measuring current, and that this thing is responsible for the fourfold increase in current drain in those modes!

Anyway this little instrument makes a very convenient everyday multimeter, auxiliary meter, travel meter (since it's very small and lightweight), and its low price  and often free avialbility makes it also a painlessly disposable meter, should anything go wrong. It's simple and looks cheap, sure, but does its job well, as long as one doesn't need extremes in range, precision, and functions. I love its instant start-up, unlike highly sophisticated meters that may take several seconds to initialize.

Uni-T UT71E

 The time came when I wanted several performance features that aren't available in cheap meters, and after all, all of my previous meters were cheap ones! One such feature is true RMS measurement for AC voltage and current. Another is increased precision, which is rarely needed, but there are situations when it is at least desirable. Also most meters lose a lot of accuracy in the AC ranges when the frequency of the signal measured is far away from power line frequencies, making them unusable for audio voltage measurement; so I wanted a meter with an extended frequency range. After shopping for some time, comparing features and prices, I decided to buy this UT71E meter. Since it wasn't available in my country, I imported it from China, where it is made. This was just a few years ago, 2011 or so.
 
The specs of this meter are quite impressive. The display goes from -39999 to +39999, and there are two four-digit subdisplays.  The basic accuracy is rated as 0.05% for most DC voltage ranges, which degrades in other functions, but remains pretty good when compared to other meters. In addition to measuring the true RMS value of AC voltages and currents, this meter can also measure the true RMS value of an AC+DC combination, or it can strip the DC component, at the user's discretion. I have found this quite useful.

There are several extra functions included. The instrument is pretty capable when measuring capacitance, covering from picofarads to 40mF (yes, that's 40,000F). It can measure frequency to 400MHz, with 0.01% precision, which has rendered my old dedicated frequency counter mostly redundant, except for really high precision measurement such as needed in communication equipment.  It can also measure temperature over a pretty wide range, using a thermocouple that comes included. In the current range it has a special setting for measuring industry-standard 4-20mA loops, reading in percentage. But the nicests, greatest, sexiest function of all is that this meter will measure real power, reactive power, and power factor! For this purpose it comes with an adapter that plugs into the meter (using three terminals) and has an AC male plug and female receptable. You plug it into a wall outlet, plug any device into it, and comfortably read out the real power, total power (real plus reactive), and the power factor, on the meter's three displays! And all this with high accuracy. That's a dream come true.

The subdisplays are used in various ways. In most functions, the left subdisplay is used to show the currently selected range. In AC voltage and current functions, the right subdisplay measures frequency. When Max/Min mode is selected, the two subdisplays show the ongoing maximum and minimum values, while the main display shows the momentary value - but this assignment can be changed at will, during the measurement. 

A very often heard complaint is that digital multimeters, specially the autoranging ones, are too slow. They will take several seconds before they give a stable reading, and they can't follow variable signals very well. To fight this problem, this meter has two useful functions. One is a fast measurement mode: The main display is switched to 4000 counts mode instead of 40000 counts, with much faster update. The meter is very responsive in this mode. It almost fluently follows changes in the input signal. And the other tool is a bar graph, that's updated about 10 times as fast as the numerical display. This bar graph can be configured to have the zero at center, or at left.

Speaking about configuration, the meter has a configuration menu, that allows setting several parameters, such as auto power off timing (or disabling this function), high/low alarms, or backlight timing.

This meter has data storage functionality. It can be set up to record measured values in memory, at a selectable rate. These stored data can be reviewed later, or it can be transferred to a computer, via the included optocoupled USB interface and software. The same interface and software can also be used to continuously transfer the values measured, in realtime.

And there is more: A peak hold function, duty cycle measurement...  But let's return to basic and important specs.

It's always important to know the measurement voltages. When measuring resistance, this meter applies something that seems to be as high as 1V in open circuit, but this gets lower fast with even a tiny load. To a 10MΩ resistance it applies roughly 0.25V. So it can be used to measure resistors in-circuit, but might make semiconductors conduct in some cases. When measuring continuity, it applies -1.2V, so it will definitely make semiconductors conduct! The polarity reversal might confuse the user, too. The response to continuity is not instantaneous! There is a delay between closing the circuit, and getting a beep. That's very annoying, because it hampers searching for a connection by sliding the test probe over the pins of a connector, or such. And in diode test mode, it applies 2.8V, which is marginal for testing white and blue LEDs, but fine for everything else. It will just barely light white LEDs a little bit, and keep displaying the out of range sign. All these things should have been better, in an advanced multimeter like this one .

This meter is protected against overloads up to 1000V in all the ranges that are used through the main input. This is an excellent safety measure for everyday use with all the accidents that tend to happen.

And now let me tell you my biggest grief: This darn multimeter uses a 9V battery, and consumes no less than 9.4mA in the basic functions, and 11.3mA in some other ones. So a 9V alkaline battery will last maybe 30 hours! That's awfully poor. I was quite shocked when my first battery ran out of juice after just a few days of using this meter! Several batteries later I figured out that this multimeter was a power hog, and decided to use it with rechargeable batteries. I bought two "9V" NiMH batteries, which are actually seven cell 8.4V, 200mAh ones. They last about 20 hours, and at least this meter runs perfectly on those NiMH batteries. Every few days of moderate use I have to open the battery compartment and swap the batteries between the meter and the charger. Almost as bad as a smartphone... only that with a smartphone you don't even get the chance to swap batteries, but are stuck with a single one!

I soon put away the screw of the battery compartment. It would wear out too quickly, and my patience too. I just push the battery box in, as it fits tightly enough not to fall out.

This meter is relatively free from additional quirks. I just would like to mention one that sometimes disturbs me slightly: This is an "intelligent" meter, and sometimes it seems to think it's more clever than it really is. When trying to measure a very low value, suddenly the display will change to 0.0000. Apparently there is a threshold below which an auto-zero function activates, obliterating the signal to be measured! It only happens with very tiny signals, though, so it's not too bad. But was it really necessary to do this in the meter's software?

Uni-T UT61A

My old Yu Fong is still my main multimeter, the one I use most, despite its propensity to constant beeping and the need to plug the positive probe into another hole about 642328324 times a day. The Cen-Tech can't replace it because it's just too basic and flimsy. The UT-71E can't replace it either, because of its outrageous current drain that has me spending almost more time changing its battery than doing electronics. So a few weeks ago I got weak and decided to buy yet another multimeter. I wanted a relatively simple, straightforward, inexpensive, but decent quality autoranging multimeter. The choice fell on another Uni-T, because this is the only brand I can buy locally that combines acceptable quality and price. And the model chosen was the cheapest one of that brand that I could get here: The UT-61A.  I didn't decide the purchase just based on the price, but I did compare specs with several other meters, before choosing this one.

This is a relatively straightforward multimeter, although it does include several extra functions, like most modern meters do. Its display goes from -3999 to +3999, and the rated basic accuracy is 0.5% in most DC voltage scales, degrading to around 1% in AC and current ranges. It measures resistance to 40MΩ. It uses around 0.44V to measure resistance and continuity, which is fine, and about 2.9V for measuring diodes, which is fine for most uses but a little short for white and blue LEDs. It will just light them, but won't display the voltage.

The extra functions of this meter include frequency to 10MHz, capacitance, transistor gain, and a very nice "sniffer" function in which it detects electrical fields, without any contact. This can be used to find wires buried in a wall, to tell live wires from neutral wires, and so on. It also has a max/min function, data hold, and relative (offset) measuring. A backlight is present, and an auto power off function that can be disabled.

In every AC range (V, A, mA, A) it can be switched into showing the frequency and the duty cycle, with limited range. This is in addition to the full range, dedicated frequency/duty cycle setting.

For measuring components, the meter comes with a convenient plug-in module that accepts legged and SMD resistors, capacitors, diodes, transistors, etc.
 
Now the quirks: When measuring capacitance, there is a whopping internal 10.19nF capacitance, which needs to be cancelled by using the relative measuring function.  It's not a big problem, but it's inelegant!  More of a problem is the slow response in the continuity mode. Like the other Uni-T, this meter cannot be used to quickly search for a connection. It simply takes too long to beep, after making contact. Unfortunately the data sheets never tell about this little but very important spec! Also, in DC voltage mode, the meter defaults to the lowest range (400mV), which has an extremely high input impedance, so the meter picks up typically around 300mV and stays there, until you connect the test leads somewhere. No nice clean zero dot zero reading! In AC voltage instead it defaults to the second lowest range, which has low enough input resistance, avoiding this problem.

I haven't used this meter much in practical work yet, given that I bought it just two weeks ago. So I can't yet give you a final report on its usability. But the autoranging seems quirky too: The meter seems to take pretty long (several measurement intervals) until showing a stable reading, and when measuring in high impedance circuits, this can lead to repeated range switching as the measured value changes due to varying meter load. In the few days I have been using it, several times I have seen it continuously switching forward and back between two ranges, forcing me to use manual ranging. Optimally a meter should have a constant input resistance, but few multimeters do.

The protection of this meter is as good as that of the UT71E: 1000V in all ranges used through the main input. You can set it to resistance and then plug it into the wall outlet - no damage done!

This meter also uses a 9V battery, and draws 2.8mA from it in most functions, and 3.0mA in the current ranges. So it should deliver around 120 hours of service from a 9V alkaline battery. That's far better than the UT71E or the Mastech clamp meter, but it's many times worse than the 30 year old Yu Fong, or the ultra cheap Cen-Tech. I wonder why these modern multimeters are such power hogs! I would expect modern technology to use less power than ancient one, but when it comes to multimeters this logic seems to be reversed: The analog meters use zero power, the old Yu Fong autoranging digital meter uses 1.2mW,  the cheap Centech from around ten years ago uses 7.2mW, and the modern Uni-T meters use 25 to 100mW! It seems to be an exponentially increasing curve.

The auto power off function of this meter is a nuisance. Every few minutes it will go "BEEP BEEP BEEP BEEP BEEP BEEP" like crazy, and if I don't quickly attend to Mrs. Meter and change function or hit a button, she will switch herself off. So the meter has to be used with the auto power off function disabled, but since there is no configuration option to disable it permanently, it's necessary to disable it each time one switches the meter on, by pressing the blue button during power-up.

Other meters I have used

The meters shown on this page are just the ones I have owned and used at home. During my professional life (yes, I did have one!) I used a lot of different multimeters. Many of them were Fluke meters - after all cost was almost no issue where I worked. I remember the Fluke 73, 75, 87, and 87-3, at least. All of them were reliable performers, with varying features, and they were almost impossible to kill. The Fluke 87 on my workdesk was the first of that model bought by the organization. I remember it as a good meter, but a terrible power hog - the 9V battery had to be replaced at least once a week. The Fluke 87-3 I got a few years later was far more conservative in its power requirement.

There was a very basic manual ranging digital multimeter on my desk, when I just arrived. I think it was a Hioki. I didn't use it much, since it was already old and worn, giving unreliable measurements. But there was also a pen-like meter, powered by two button cells. It measured just voltage, resistance and continuity, with a beeper, and was very practical and good. I used it a lot, for many years, but can't remember  the brand and model now. It had a gray body with an orange front end.

On the fun side, there was a very old digital desktop multimeter, using Nixie tubes. A big, heavy box. It could have been an HP, but I'm not sure now. It was manual range, and worked quite well.

I have also used a wide assortment of cheap analog and digital meters when visiting other people, and during my university years. That includes ancient but excellent Simpson analog meters, FET-input Philips analog meters with constant 10MΩ impedance, a Heathkit VTVM, and so on. And I have been confronted with ultra cheap, 2kΩ/V micro analog meters, that have about 10% full scale accuracy, at best.

My dream multimeter 

I would like to buy yet another digital multimeter. One that works as I want, so that it could be a good replacement for my old and worn Yu Fong. Maybe you will be interested in knowing what this ideal basic everyday-use meter of my dreams should be like. So, here I go:

- It should be an autoranging multimeter, with manual range override.
- It should have voltage (DC and AC), resistance, continuity with beep, and diode test. Any additional functions are welcome but optional.
- It should be "indestructible", that is, protected to 1000V or more in all ranges.
- It should have reasonable resolution and precision. 2000 counts is OK, 4000 counts is great. 0.5% accuracy is all I need.
- It should be fast. Worst case delay from applying a stable signal, to getting a stable reading, should be less than 0.5 seconds. This must include the time required for all range determination and switching operations.
- There should be an even faster bar graph, for unstable signals. An update rate of at least 20 times per second is desirable.
- Continuity and resistance tests should be done with no more than 0.4V, while diode tests should go up to at least 3.5V displayed value.
- The input resistance in voltage mode should be constant over all ranges. 10MΩ is fine. If not constant, at least it shouldn't vary very much.
- In AC it should have true RMS response, optionally switchable to peak response.
- The frequency response in AC should extend at least over the full audio range, with reasonable accuracy.
- It should use AA batteries, because those are most cost-effective. 3 cells is perfectly acceptable, if needed to provide enough diode test voltage.
- Current drain should be low enough to guarantee at least 1000 hours battery runtime. The more, the better. The ultimate goal should be over 5000 hours.
- There should be no auto power off function.
- The beeper should be used only for continuity testing, and perhaps for any urgent alarm conditions. No other beeping is desirable.
- Continuity testing should have instant response.
- Backlight is a nice feature, but totally optional. I hardly ever need it.
- The test probes shouldn't need to be moved between different sockets. Ideally the test probes should be soldered to the meter, but still user-replaceable.
- All functions should be selected with a single rotary switch. Any pushbuttons to cycle through functions are undesirable.
- The power switch should be separate from the function selector.
- Startup should be essentially instantaneous. 
- The price should be reasonable.

Please let me know if you ever find such a meter!


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