Multimeter purchase help request

[badsign]

Hi folks.

I've been stuck in a loop while researching. Google searches. Forum post reading. AI agent Q&a. YouTube reviews.

I recently successfully created a esp32 based wearable device on a breadboard. But when I moved on to the PCB design phase I ended up with a handful of bricks due to some basic skills being undeveloped. The entire project was supported by AI. I've learned a lot about what I don't know and how skeptical I need to be of AI guidance.

So I've decided to back up and fill in some knowledge gaps. I'm starting off with the book "Make: Electronics". Once I've gone through the entire book i will go back to my esp32 project for a second attempt.

Where I need your help is with finding a meter that will get me through the book as well as support my work down the road with microcontrollers. I have no plans for working with anything high voltage. I do have an old 1980s vintage synth that id like to work on some day in the future but that's not really an immediate need.

From what I've gathered I need something with a quick beep response and ability to measure µA with good accuracy. I've also read to keep an eye out for how much load the instrument introduces as that could be an issue specifically with esp32 sleep cycles, not really sure I understand that very well. I'll also be looking into other chips than esp32 as my experience builds  Some meters come with temperature measuring, not sure if I'd need that.

I'm based in the USA but I'm open to international purchases. I don't strictly have a budget in mind but I've seen these things going for several hundred usd or higher and since I'm a beginner I'd prefer to keep things below 100 if possible, but willing to stretch if there's a good reason for it.

Anyway, any insight you all can provide would be really appreciated. I'm overwhelmed by the options and genuinely do not have the skills to make an educated decision.

Editing to add at one point I also saw a recommendation to supplement the meter with something like a uCurrent Gold to cover the readings needed by something like an esp32. I'm open to similar approaches that pair more than one item to get the coverage is likely need.

[calzap]

Define the bottom range on current more precisely.  Measuring 1 µA with good accuracy versus 100 µA requires different equipment and special techniques.    Mike

[badsign]

Hey Mike. Thanks for the input.

A little googleFu turned this up...

Active Mode: Up to 240mA
Deep Sleep Mode: As low as 5μA
Modem Sleep: Typically 10-20mA

[Aldo22]

ZT-225 should be sufficient.
The image shows 5.06 μA

For example:
https://www.aliexpress.us/item/3256807070617531.html

[IanB]

It seems like you might want to measure the current draw of the microcontroller. Current measurement puts a series resistance in the circuit, which can affect the circuit operation. The parameter you want to look for in the specifications is "burden voltage".  This gives an indication of how much voltage will be dropped by the meter when measuring a given current in a given current range. The µCurrent Gold is a device that gives a much lower burden voltage on low current measurements when used together with a regular multimeter.

For simple electronics use you don't need to pay a lot for a meter, but it is worth paying a bit more for higher quality. You will get better reliability and better robustness. There are some good quality brands at reasonable prices, like Brymen for example.

You might consider having two meters, so you can do two measurements at the same time, like current and voltage.

[Doctorandus_P]

For around USD 100 you can buy a quite good Brymen meter. Brymen is a brand that makes good meters for a reasonable price. At a local shop I see I can buy the BM231 for EUR 72. But my guess is that it's a better meter then you need.

I would avoid the "cheapest" stuff. Brands like Fnirsi and Aneng is pretty much garbage. If you're lucky, it works for a bunch of years (and thus you can find good reviews). If you're unlucky, the meter fails after a few weeks, or it gives false readings, which is even worse, because it's hard to diagnose as a beginner.

For around EUR 30 to EUR 60 you can buy a meter with a quite reasonable quality and functionality. But I don't know what the performance to price ratio is with these meters.

I have a Dynatek112 (bought new) and a MeterMan 35XP (bought second hand for EUR25), and both these meters are over 30 years old and still working perfectly.

For the uCurrent gold. It's simple: you don't need it. I can see it's attractiveness for people who want a reliable insturment and don't care much about the cost, but it's just a simple opamp based 100x amplifier and some shunt resistors. You can build a similar device yourself for < USD 10 (The connectors and box will be most of the cost), and when you spend some time to calibrate it, accuracy will be similar to the DMM you calibrate it with. Also: Designing and building a variant of the uCurrent is a fun beginners project.

Some of the UNI-T meters are apparently quite reasonable, but others are not. If you want to buy Uni-T, then be careful.

[Doctorandus_P]

I scrolled though the book:
https://arl.human.cornell.edu/linked%20docs/Make%20-%20Electronics.pdf

and I quite like it. Seems like a good beginners book. But it is (of course) not complete. There is not a single book that can cover the whole area of electronics.

One thing that is missing is the usage of operational amplifiers. (a.k.a. Opamps). The book "Opamps for Eveyone" (a.k.a. slod006b) is a quite good (and free) book about opamps.

[ledtester]

From what I've gathered I need something with a quick beep response and ability to measure µA with good accuracy. ...

One problem is that multimeters measure uA by inserting a largish value shunt resistor into the circuit. This is fine if the microcontroller stays in sleep mode, but the typical MCU alternates between sleep and doing a lot of work. If you draw a lot of current with a large shunt resistor in circuit the power rail will droop a lot potentially affecting operation of the MCU.

About two weeks ago this video came out suggesting using a diode in parallel with your own shunt resistor:

Measure micro Amperes with any multimeter -- The Design Graveyard
https://youtu.be/BIFLfk8ItCU

This allows you to measure the sleep current even when your MCU is periodically waking up.

With this approach you only need a multimeter that can measure millivolts - which pretty much any multimeter can do.

[J-R]

Are you saying you don't have a DMM at all right now?  Or are you needing to add one to your bench with a focus on those low-current measurements?

[BillyO]

I would 2nd Aldo22's recommendation of the ZOYI ZT-225.  Even considering Orange Poopy-Pants tariffs.

It has a stunning set of specifications for it's price.   It's accurate, well built and well protected.  I have tested it to 1.5kV on the DCV, ACV, and ohms ranges without damage.

As to measuring uA, it will measure down to 1uA on the mA range with a burden resistance of only 1.3 ohms.  If need be it will measure down to 10nA on the uA range with a burden resistance of 100 ohms.  Neither of these ranges should affect the operation of a MCU in sleep mode drawing under 100uA which, even on the uA range would imply a burden voltage of under 10mV.

I know some of this might be a little much to take in, but it just means this meter will do the job nicely and will fit your budget with room for beer and pizza.

[Aldo22]

As to measuring uA, it will measure down to 1uA on the mA range with a burden resistance of only 1.3 ohms.  If need be it will measure down to 10nA on the uA range with a burden resistance of 100 ohms.  Neither of these ranges should affect the operation of a MCU in sleep mode drawing under 100uA which, even on the uA range would imply a burden voltage of under 10mV.

While we're on the subject: In the “A” setting, the ZT-225 has a resolution of 100 μA with a shunt resistor of < 0.1 Ω (I measure about 0.043 Ω).
With this resolution, you can measure a very wide range (up to 20 A) with a low burden voltage.
10mA in the photo.

[Solder_Junkie]

Call me a cynic, but I wouldn't touch a Zoyi meter that claims CAT IV 600V, yet has not been independently tested. The manual doesn't even list replacement fuse types. While the OP might not currently have intensions of poking around mains Voltages, it's something that might crop up.

Dave Jones of this blog sells and recommends Brymen meters. These are independently tested to comply with UL 61010 certification. I have a couple of BM235 meters, one at each home.
https://eevblog.store/collections/test-equipment

[ledtester]

Call me a cynic, but I wouldn't touch a Zoyi meter that claims CAT IV 600V, yet has not been independently tested. ...

fwiw, the OP has stated:

Where I need your help is with finding a meter that will get me through the book as well as support my work down the road with microcontrollers. I have no plans for working with anything high voltage. ...

[badsign]

Thank you all for taking the time to respond. I'll reply individually below, but to summarize things, I do plan to eventually buy a Brymen meter, once I have a better understanding of my needs.

In the meantime, I picked up the Zoyi ZT-225 based on Aldo22 and BillyO recommendations. Hard to argue with all those features for ~$22.

I understand there are some safety concerns but if it makes you all feel better that I'm not going to kill myself, the meter will only be used on my desk with low voltage applications. I will invest in a properly certified meter down the road well before I venture into anything that can do any physical harm but to be honest electricity scares the hell out of me so I don't imagine ever venturing out of Class I and II applications.

OK, on to the individual replies.

ZT-225 should be sufficient.
The image shows 5.06 μA

For example:
https://www.aliexpress.us/item/3256807070617531.html

Hard to argue with the price. Picked one up for ~$22 shipped. Should be here within the week.

For simple electronics use you don't need to pay a lot for a meter, but it is worth paying a bit more for higher quality. You will get better reliability and better robustness. There are some good quality brands at reasonable prices, like Brymen for example.

In all likelihood, I will end up with one of the Brymen at some point. Picking up something that does what I need to keep moving through the book buys me some time to figure out "what I don't know" so I can make sure I'm choosing the right one once the price is $150+.

For around USD 100 you can buy a quite good Brymen meter. Brymen is a brand that makes good meters for a reasonable price.

I would avoid the "cheapest" stuff. Brands like Fnirsi and Aneng is pretty much garbage.

For the uCurrent gold. It's simple: you don't need it. ... Designing and building a variant of the uCurrent is a fun beginners project.

Best I could find for a BM235 was ~$160. Not an unacceptable price point once I know what I'm actually paying for. I picked up one of the ZT-255 that was recommended a few times. It was super cheap in cost and should buy me plenty time to make an educated purchase when it's time to get the second meter.

I scrolled though the book:
https://arl.human.cornell.edu/linked%20docs/Make%20-%20Electronics.pdf

and I quite like it. Seems like a good beginners book. But it is (of course) not complete. There is not a single book that can cover the whole area of electronics.

One thing that is missing is the usage of operational amplifiers. (a.k.a. Opamps). The book "Opamps for Eveyone" (a.k.a. slod006b) is a quite good (and free) book about opamps.

Thanks for the recommendation on that free book. Agreed you can't learn an entire field of study from a single book or course. Hopefully it gets me started on the right foot.

Are you saying you don't have a DMM at all right now?  Or are you needing to add one to your bench with a focus on those low-current measurements?

I have an Innova 3320 that I bought about 12 years ago.

I would 2nd Aldo22's recommendation of the ZOYI ZT-225.  Even considering Orange Poopy-Pants tariffs. It has a stunning set of specifications for it's price.   It's accurate, well built and well protected.  I have tested it to 1.5kV on the DCV, ACV, and ohms ranges without damage.

I know some of this might be a little much to take in, but it just means this meter will do the job nicely and will fit your budget with room for beer and pizza.

Thanks for sharing your experience. I always appreciate having leftover money for beer and pizza. I read more about the meter and watched it in some YouTube videos and it seemed like it'd be a good enough place to start. So, I ordered one.

Call me a cynic, but I wouldn't touch a Zoyi meter that claims CAT IV 600V, yet has not been independently tested. The manual doesn't even list replacement fuse types. While the OP might not currently have intensions of poking around mains Voltages, it's something that might crop up.

Dave Jones of this blog sells and recommends Brymen meters. These are independently tested to comply with UL 61010 certification. I have a couple of BM235 meters, one at each home.
https://eevblog.store/collections/test-equipment

I hear you loud and clear and I appreciate that you're looking out for my safety. I also saw the same concern raised elsewhere during my research. As mentioned  above, I more than likely will end up with a Brymen meter, but this ZT-225 for ~$22 gets me moving forward with the studies and when I know more I'll be better equipped to choose an appropriate higher end meter.

[badsign]

fwiw, the OP has stated:

Where I need your help is with finding a meter that will get me through the book as well as support my work down the road with microcontrollers. I have no plans for working with anything high voltage. ...

Correct. And also thanks for that Design Graveyard link. Forgot to tag you in the individual replies in my previous post.

[Solder_Junkie]

"Best I could find for a BM235 was ~$160"

Ouch, in the UK that meter from an official outlet (Telonic) is 73 GBP plus tax. I thought prices here were high.

[Doctorandus_P]

BM235 is EUR 92 here in the Netherlands. (Approx USD 110).

https://www.eleshop.nl/brymen-bm235-multimeter.html

With a blue holster it's a bit more:
https://eevblog.store/products/eevblog-bm235-multimeter

In the USA you can buy Brymen meters with a green holster and with the "Greenlee" label printed on it.

[Aldo22]

In the meantime, I picked up the Zoyi ZT-225 based on Aldo22 and BillyO recommendations. Hard to argue with all those features for ~$22.

$22? That's almost too good to be true.
You sometimes see deals like that, but I'd have my doubts.
Hopefully everything works out. 

[BillyO]

While the OP might not currently have intensions of poking around mains Voltages, it's something that might crop up.

It will be fine for 120V on his bench, as long as he doesn't use it in his breaker panel during a thunder storm.  As I said, I tested mine to 1500V on DCV, ACV and Ohms .. for several minutes.  No breakdown, no arcing, no explosions, no damage.  The unit is very heavily built, at least as heavy as any Fluke or Byrmen I have, with an enormous rubber outer sleeve, so if there was a fuse explosion, it would have to be one heck of doozey.  Not something you are ever likely to see at the power strip on you bench.

I guess it should not surprise me that people will be quick to denounce something they have zero experience with.  It's eevblog nature.

The fuses are a standard size.  Replace them with the best fast blow fuses you can get in that size.

[badsign]

"Best I could find for a BM235 was ~$160"

Ouch, in the UK that meter from an official outlet (Telonic) is 73 GBP plus tax. I thought prices here were high.

Right. And when I started looking at future-proofing my purchase, I was looking at the BM2257 with the optical cable for logging and that was pushing $200 USD. So, yeah, I'll still aim to acquire a Brymen but it's gonna be a little while to make sure I get what I need specifically.

BM235 is EUR 92 here in the Netherlands. (Approx USD 110).

https://www.eleshop.nl/brymen-bm235-multimeter.html

With a blue holster it's a bit more:
https://eevblog.store/products/eevblog-bm235-multimeter

In the USA you can buy Brymen meters with a green holster and with the "Greenlee" label printed on it.

The only issue is that the Greenlee equivalent products are even more expensive than the Brymen version after accounting for shipping and fees. Crazy.

In the meantime, I picked up the Zoyi ZT-225 based on Aldo22 and BillyO recommendations. Hard to argue with all those features for ~$22.

$22? That's almost too good to be true.
You sometimes see deals like that, but I'd have my doubts.
Hopefully everything works out. 

lol yeah I was definitely concerned but before I pulled the trigger I did a little research. The listing was from the ZOYI multimeter discount shop, and they share the same business license as the vendor from the listing you provided. It was also my first Ali Express purchase so I got a discount from that. Here's the listing, normal price is just over $30: https://www.aliexpress.us/item/3256810203808902.html. Since I was under $29 I had to pay shipping, but there was a $2 off coupon that covered the shipping. The listing also claims the meter ships from the USA and that I'd have it by the end of the week. I was fully expecting to place an order and wait 3+ weeks for delivery from China. Not bad 

While the OP might not currently have intensions of poking around mains Voltages, it's something that might crop up.

It will be fine for 120V on his bench, as long as he doesn't use it in his breaker panel during a thunder storm.  As I said, I tested mine to 1500V on DCV, ACV and Ohms .. for several minutes.  No breakdown, no arcing, no explosions, no damage.  The unit is very heavily built, at least as heavy as any Fluke or Byrmen I have, with an enormous rubber outer sleeve, so if there was a fuse explosion, it would have to be one heck of doozey.  Not something you are ever likely to see at the power strip on you bench.

I guess it should not surprise me that people will be quick to denounce something they have zero experience with.  It's eevblog nature.

The fuses are a standard size.  Replace them with the best fast blow fuses you can get in that size.

Yeah, I saw 2 videos on YouTube where the ZT-225 was connected to high voltage. One was directly connected to mains (I'm still a little fuzzy on the use of 'mains' but he had some leads that were apparently connected to an outlet off screen). The other was a shootout of $30 meters and I believe the person was pushing power out via a bench supply and was routing it through a Brymen meter and then into the meters being tested. I was kind of surprised the things didn't start smoking but apparently they can handle some heat!

Good to know that the meter can handle the higher voltage, even if I don't plan to encounter that scenario.