DROKDigital Current Tester Multimeter DC 100V Volt 2A Ampere Battery Monitor Gauge 2in1 Red/Blue 2-Color LED Display Car Automotive 12V 24V Built-in Shunt

This is an amazing little device for the price. I wired it into a plastic box with a switch connecting the thin black and red wires to a small 9 volt battery. I fitted two plugs for input and output. In my case the input was a solar panel and the output was the car battery. The thick red wire is connected to the input positive lead. This measures the voltage from the solar panel. The thick yellow and black leads measure the current in amps flowing through the negative lead. So the yellow was connected to the input negative plug connection and the black was connected to the negative connection on the output socket.This works flawlessly measuring the current going from the solar panel to the car battery. Since I have a panel about one foot square I bought the 2 amp version of the DROK which has the correct size shunt resistor built in. How does this work? Well the resistance calculated to produce a 0.075 volt drop across the resister at the maximum current of 2 amps. The 10 amp version is the same but you use a resistor calculated to give a 0.075 volt drop at 10 amps. Some models have a resistor that you buy separately depending on how many amps you want to measure. The formula is 'good old Ohm's law' E=IR where E is voltage (emf), I is current in amps, and R is resistance in Ohms.So there you have it. A prefect little device at an incredible price. Well worth 5 stars!

The instrument works as it should but the instructions are horrible.

wiring not explained well. because of internal grounding it is to complicatedto set up. Cant get both voltmeter and ammeter to work well together.btw I'm an electronics engr.

This is a very nice little volt/ammeter. However, the wiring color and size is a bit confusing and not necessarily intuitive. It worked very well once I understood the wiring. What you need to know is that the 2 black wires and the yellow have a common, internal ground (yellow is effectively grounded thru the shunt). Thus, the ammeter shunt can only be inserted into the negative line betweenyour pwr supply and load. I. E., The large black wire connects to your pwr supply 12 volt negative line. (The small black is not needed.) The large yellow lead connects to your load negative line. NOTE do not connect your negative line ( eg., Battery cable) from the 12 volt supply to the load. Both red wires connect to 12V pos. Keepin mind that the ammeter shunt, which is connected internally between the large yellow and large black leads is internally connected to the load negative, the shunt can only be in the negative side of your circuit. It is unclear to me why one red lead is large. This can be misleading because it is a low current lead.

Ordered this meter 10mo's ago and just getting around to testing it out. Ordered 3 different units. The other 2 worked fine and as expected. But couldn't get this current meter part to work at all, no matter what configuration I tried. The diagram(s) that came with it is useless. If they are going to show a shunt, then there should be a dashed line around it and the meter to shown it's all internal. Even with that in mind, I couldn't get it to work. Obviously others have - they gave it 4 and 5 stars.

No good instructions for connecting it. Still sitting on the shelf.

These meters come in many Volt/Amp values, some with shunts, some without and with different wiring even with the same rating. This particular meter is rated 4.5V-100V and 2A. On the sample I tried I found that the voltage reading was pretty close as it arrived (and you can calibrate it yourself). The current was also close. The shunt is built-in on this version. I ran it up to 5A with no problems and up to 8A which caused noticeable heating, so I wouldn't recommend going there very long. Of the versions I've looked at, this was the most linear at low currents, down to 0.1A or so. Very compact and the price is right. Like it a lot.

I bought this as a replacement for a SMAKN volt/amp meter( that was defective out of the package) and looks identical from the front. This DROK volt amp meter is just what I needed. The wires carrying the current look like they will actually carry current up to 10 Amps for a period of time, without melting the insulation. The wires on the SMAKN meter looked to be too small a wire gauge to carry 10 amps at all. When I measured the current (10 ohms@10w at 10V to get 1 AMP) I was amazed to see that the DROK meter was very close to 2 Fluke meters I used to read the same values. I could tweak the calibration adjustments on the back of the DROK meter to get it closer, but the circuits I've built thus far, aren't that sophisticated to need .01 accuracy and I'm not certain of the instrument calibration of the Fluke meters. This volt/amp meter is small and has a bright display. As others on this site have mentioned, no instructions come in the package so print off what you see on Amazon to get it connected correctly.