Review: £10 multimeters - Now includes the new RS-14!

[Murphyv310]

Hi.
Again what an excellent multimeter. As a frequency counter it works well with my signal generator up to around 18kHz 

Typo. 18mhz.

[Mark Hennessy]

As a frequency counter it works well with my signal generator up to around 18kHz then it reads low and above 21mhz the reading  jumps around, a two transistor rf amp restores the readout up to around 50mhz, I'd suspect with more drive then higher frequencies could be measured, a dedicated frequency counter would be more practical though.

Curiously, my AN8002 is considerably more sensitive than my AN8008:

AN8002:
The sensitivity is very good. At low frequencies (<100kHz), it's about 20mV RMS (sine wave). At 1MHz, it's roughly 40mV. At 10MHz, you need just over 1.2V, and at 30MHz, 1.5V. As mentioned, I managed to get to 80MHz with the +17dBm (1.6V) from my RF generator, so it's interesting that the response essentially plateaus after the initial rise between 1 and 10MHz. Unless I've missed it, there's no specification given for sensitivity.

AN8008:
This is another one that requires the signal to cross 0V when measuring frequency. I found that the sensitivity was rather less good than the AN8002. At low frequencies (<1MHz), it's about 600mV RMS (sine wave). At 10MHz, it's roughly 1.4V (the AN8002 was 1.2V), and the highest the +17dBm (~1.6V) from my RF generator would get me was 80MHz.

Both those were in the dedicated "Hz" function though - they obviously differ on the AC Volts function. The AN8008 is less sensitive in this mode, thanks to what appears to be an auto-ranging bug:

There is a bug with measuring frequency on the voltage ranges. You need a minimum of ~1.7V to get a reliable reading, whereas the AN8002 works down to about 50mV, give or take, on a 1kHz sine wave. With a lower input voltage, if you use the yellow button to cycle back to AC, then press it again to get Hz, you get do a reading for about 3 seconds, then it changes to 0Hz. This works reliably down to about 100mV. I think what's happening here is the meter is erroneously auto-ranging higher voltage range, rendering it less sensitive.

But ultimately, I agree that a dedicated frequency counter is the best bet, especially if you can drive it from the Y-out of your oscilloscope if it has one (I wish more 'scopes had that). It's definitely a "nice to have" in a multimeter, and the fact it goes beyond a few 100s of kHz is quite surprising, given the way the signal is being handled internally.

Apparently some samples of the AN8002 don't have Hz and duty cycle on the Volts function. Do any of yours fall into this category, Trev?

Cheers,

Mark

[Murphyv310]

Hi Mark.
Both the AN8002's that came yesterday have the frequency and duty cycle modes accessible through the voltage function. If the third one comes I'll check that one as well.

[Murphyv310]

Hi
I see there is a new model the AN8009. Better specced than the 8008 with the resistance range for example reading up to 100 meg ohms.

[Mark Hennessy]

Yes, that's been out for a while now. It's good that it fixes the 9.999M restriction of the AN8008

Compared to the AN8008, it adds temperature (and the probe appears to be a bit better than the usual bare thermocouple), and a NCV detection feature (which is not something that excites me greatly on a multimeter). The square wave output is gone, but that's no loss IMHO.

So if you have neither, the AN8009 is now the one to go for. But if you already have the AN8008, that's a harder decision.

The AN8009 has the same current ranges, so if the gaps in the current ranges bother you, then look elsewhere...

Which leads me onto the BSIDE ZT301. This is a slightly larger meter, but obviously from the same people. I haven't got around to writing up my findings properly yet, but I did an initial review here: http://www.eevblog.com/forum/beginners/o...msg1344853

This one is 8000-count. There is the ZT302, which is 9999-count, but on balance, I think the ZT301 is the best one...

I've got about half a dozen more meters to add to the reviews section, including some pocket types. Just need to finish the time machine

[The Philpott]

The DT3266L deserves a mention, although it is firmly steered towards the jobbing electrician rather than electronic/audio work.

There are several different versions, my 'L' model has less bells and whistles than some variants, but does have plus points, not the least of which is that is was found in a skip a few years ago in the pouring rain, without leads, but in working order. If i was to try it on Mains, i would have the back off it for at least a visual check.   i haven't checked accuracy apart from resistance, which is quite good for this end of the market.

Limitations of this version:
Resolution 1 ohm, 1 volt AC/DC, (Clamp only- 10mA AC)
No DC current facility as the 'L' lacks a hall effect sensor.
The AC and DC symbols could, and should, be larger and clearer.
Maximum resistance measurement 2Meg

Good points:
Screen Hold
Rotary selector quite precise despite small size
Mains voltage sensing LED, Black lead insulation held in hand and Red Probe touched to test piece. (Thinks: Is this a good or a bad thing..?)
Feels quite robust, good screen contrast.      

   

[jimmc101]

Just a quick heads-up that the AN8002 is currently on offer from Banggood at £9.98 with free shipping  AN8002 offer

Jim

[ex 2 Base]

Just recovering from an Hernia job and spent an interesting two hour reading all the comments. Mark does a wonderful job reviewing the meters and following his recommendation I bought a UNI-T UT210E some time ago, just for the DC amp clamp facilities . Ted