David L. Jones writes:
A current adapter for multimeters?
“But don’t most multimeters already have current measurement ranges?” I hear you ask. Well, yes, they do of course. But most multimeters, be they a no-name $10 hardware store throwaway model, or a $1000 highly accurate brand name meter, all suffer from two rather annoying issues with their current measurement ranges – burden voltage and reduced accuracy.
The biggest problem with current measurement ranges is called “burden voltage”. This is the voltage that the internal current shunt resistor drops as you pass your circuit current through it. The burden voltage is typically specified in millivolts per Amps (mV/A). The value will change for different current ranges, so you might have 1mV/A, 1mV/mA, or 1mV/μA for example.
Normally you may not give burden voltage a second thought, as like many, you probably think it’s fairly insignificant in most applications. In fact, most people would be hard pressed to tell you what the burden voltage of their particular multimeter actually is. It’s usually buried away in the user manual, if it’s mentioned at all. Next time you borrow a colleague’s meter, ask them what the burden voltage is, and watch their reaction…
µCurrent – A Professional Precision Current Adapter for Multieters - [Link]
With the MS2102 clamp multimeter you can comfortably measure not only alternate but also a direct current and voltage and all this at an outstanding price.
If you´re considering a purchase of a clamp multimeter, or if you already have a common multimeter and want a clamp version, then we have the device with an outstanding ratio of price to performance for you.
Sometimes it isn´t a problem to disconnect a measured circuit and to measure current by a common multimeter connected in series. However you may have already experienced a situation when it wasn´t possible to disconnect the measured circuit, from mechanical or electrical reasons. For these situations a clamp multimeter is an ideal choice. As it is well known, the biggest advantage of clamp multimeters is that they are able to measure a current flowing by a wire lead on the base of an induced magnetic field – without direct connection to a measured circuit. Thanks to the fact that a current is measured indirectly – the multimeter is at measuring galvanically isolated from a measured circuit, what provides a significantly higher safety to the user. From the principle of construction is the clamp multimeter suitable for measuring of mid to higher currents (above approx. 10 mA)
A big advantage of MS2102 is that it enables to measure also a direct current (DC). So for example to measure a current flowing to or from a car battery is with this device a breeze. Concurrently with measuring AC and DC current offers MS2102 also a possibility to measure also an AC and DC voltage, resistance to 400 Ohm and a continuity test. It contains an analogue bargraph and a maximal display value is 3999.
Measure even a direct current with the clamp multimeter MS2102 - [Link]
I bought this multimeter (Minipa ET-870C) a while ago for $17, great value. I got it because its nice to have around multiple meters for when you wanna measure both input and output voltage/current. I believe it was advertised to have an auto-off feature for 15 mins but it didn’t. This eventually lead to many drained batteries because I often forgot to turn it off after using it. So during a boring weekend when the weather outside was bad I decided to add this nice feature to the meter. I knew it had to be a small circuit to be able to fit inside the multimeter so I picked the tiny25 the smallest micro I had around.
Adding auto turn-off to a cheap multimeter - [Link]
Kerry D. Wong writes:
Most of the multimeters do not offer resistance measurement in the milliohm range. In most meters a typically Ohm range has an accuracy of 0.1 ohm and is too coarse for measuring small resistance. Of course, some of the high-end multimeters have milliohm range and there are also dedicated micro ohmmeters for even more accurate small resistance measurements, but most of them are priced way out of the range for personal use.
Accurate Milliohm Measurement - [Link]
For today’s “Toolsday” we’ll be looking at the EX210 multimeter by Extech. It’s a mid-range meter that’ll take all your standard hobby readings like resistance, continuity, voltage, and current, but it also boasts an infrared thermometer and a backlit display. [via]
Toolbox Review: Extech EX210 Multimeter – [Link]
Simple meter on a HD44780 and Attiny13. This project has born from a pure curiosity – what we can made on this small uC? We can, and a lot. In this case this tiny will measure voltage, current, and temperature, recalculate, and in a nice way show on a 16*1 lcd. Despite on unusual solutions and few defects, it still can be used as a power supply meter. PCB dimension – only 35mm x 16mm
HD44780 and Attiny13 multimeter - [Link]
What’s inside Gossen Metrawatt’s Metrahit Energy Multimeter?
Gossen Metrahit Energy Multimeter Teardown - [Link]
The iDVM digital multimeter from Redfish Instruments Inc. wirelessly connects to an iPhone, iPad, or iPod Touch to enable users to acquire, visualise and share measurement data on their Apple devices. Unlike conventional multimeters, the iDVM does not have its own display or controls, but instead piggybacks on the iPod, iPad or iPod Touch screen with the aid of a special app. According to Redfish, this novel approach provides instrument users with a familiar user interface that allows them to interact with electronic test and measurement tools in a previously impossible manner. [via]
Multimeter module links to iPhone or iPad – [Link]