Current – VoltLog

Voltlog #280 – TPS62840 olmBoard Ultra Low Power Step Down Converter

Welcome to a new Voltlog, in this video we are taking a look at the TPS62840 ultra low power step down converter from Texas Instruments. It’s basically a buck converter with an input voltage of 1.8-6.5V, 750mA output current, with a quiescent current of just 60nA and active current of just 120nA. It also features very good efficiency at light loads of just 1uA it can offer 80 percent efficiency.

Other features include 16 selectable output voltages through an external resistor and a stop pin which when activated will completely stop any switching to eliminate any switching noise for a short moment, allowing you to take for example an ultra low noise measurement during that time. During that take power will be sourced from the output capacitors. So it looks like this is a pretty interesting dc-dc converter, with really nice features and it’s optimized for ultra low power devices.

Voltlog #253 – Aneng V01A Multimeter Review & Teardown

Welcome to a new Voltlog, today it’s a multimeter review because we haven’t done one in a while and here I have the Smart Digital Multimeter which sounds like a generic name, no obvious branding on the box but granted it is featuring the multimeter on the box, it’s a color image which is not often seen on these cheap meters. On the back, the meter is shown in full black holster and we get a model number sticker, AN-V01 so this probably indicates the Aneng brand.

We’ve looked at Aneng multimeters in the past in Voltlog #114 and others and I’m gonna say this again, Aneng does not make multimeters, Aneng is just a company that rebrands existing multimeters made by other companies.

Voltlog #165 – USAMS 3 Port USB Charger With Display Review & Teardown

In this video I am taking a look at the USAMS 3 Port USB Charger With Display. Turns out the same charger is sold under many different names, and I suspect inside there is the same circuit labeled USB320G.

Like I mentioned in the past China is improving the designs of these charger each year so the situation is much better now than it was a few years back. There would still be the $2 death traps disguised as apple chargers but in the $10 range you can get some pretty decent chargers with adequate protection. This charger has the required protection features to make it safe to use however its not special in any way, the noise level is higher than I would like and the output current of just 3A is not enough for charging 3 devices. Not even 2 at the same time if they both require more current.

Here are links to where you can find this charger: Banggood, Aliexpress, Amazon.

Voltlog #132 – 4 Digit LED Panel Meter Review

Do I recommend getting this module? Yes, the accuracy is good, the resolution is nice 10mV 1mA and you also have the option for adjusting it manually for both voltage and current.

The design is pretty simple, I believe the microcontroller is an STM8S so hacking it and rewriting the firmware should be pretty easy but it already does what it’s supposed to do so I don’t see a point to hacking this module. I think you would be better off designing a panel meter from scratch.

Buy this panel meter from here.

Someone asked on youtube how should a panel like this be wired up, so here is a wiring diagram that you can use. In this wiring diagram our goal is to monitor the voltage and current for charging a battery.

Example 1 shows the panel meter connected before the battery charging module, which means it will measure everything, even the power losses in the battery charging module.

Example 2 shows the panel meter connected after the battery charging module, which means it will only measure current flowing into the battery or whatever load you have on the output.

In both cases voltage sensing is done right at the output but that wire can be moved according to your needs. Also in both cases the panel meter gets power directly from the power supply because at that point the voltage is constant.

The main thing to remember here is that these panel meters are designed for low side current sensing, that means the ground of the logic board of the meter is connected with the input of the shunt resistor.

VolLog #129 – Ebay Bussmann Fuse vs Genuine Bussmann Fuses DMM-B-44/100-R

If you remember Voltlog #117 in that video we analysed some ebay Bussmann fuses to try and figure out if they are fake or real fuses. The ebay fuses we’re way cheaper than anywhere else so that made me suspect they are not genuine.

It’s good to know if the ebay fuses are real or not because they are selling allot of them and people might be relying on these to perform as required when in fact they might be out of spec. For the average bench user which only occasionally goes up to 240VAC it might not be an issue if the fuse is slightly outside the specs but if you are probing some high energy circuit and relying on the ebay fuse to perform according to the datasheet at it is not then something serious might happen, like the multimeter could explode because of a high energy discharge or it could simply damage the meter which is to be avoided.

Links for the products and test equipment shown in this video:

Voltlog #127 – 0-60V 0-10A 1mV 1mA Panel Meter Review

So I discovered this module a few months ago and it’s been sitting in a box since then, I almost forgot about it, until a few days ago when I decided it will be a good idea to do a video on the subject.

Let me give you a few details on the specs of this module and as usual it’s pretty difficult to find the information as it’s the case with every new module coming out of China. First of all we have an input range of 0-60V and 0-10A and a 5V rail is needed to power the module itself. It has a voltage measuring accuracy of ±0.2% + 0.2% full scale which sounds strange because these figures are usually given in a percentage plus or minus a number of least significant digits. The current measuring accuracy is ±0.4% + 0.3% full scale.

The meter is basically capable of measuring with a resolution of 1mv and 1mA (however the accuracy is quite bad, as shown in the video) which is ~~quite nice~~ and ~~useful~~ (not really useful with bad accuracy) for projects like DIY power supplies or DIY electronic loads. It can also display the power in watts with a resolution of 1mW as well as showing the load impedance.

Here are some links to this product:

Voltlog #116 – UNI-T UT211B Clamp Meter Review & Teardown

today we are taking a look at the UNIT UT211B clamp meter it can do both AC and DC measurement and it has 1mA resolution on DC measurements and 0.1mA on AC. We’re also going to take a look at the DANIU P1600D test lead kit which has a bunch of accessories that might be useful.