The digital multimeter (DMM) is an essential tool in every electronic enthusiasts arsenal.
SparkFun How to use a Multimeter – [Link]
That´s why this modern multimeter is also suitable development of sensitive and “ultra low power“ devices.
Wide offer of modern measuring equipment enables us to choose a suitable device for every purpose and in various price levels. A decision which device to buy and/or a decision whether it´s worth to go for a higher-level device surely isn´t easy.
UT61D, which we want to introduce to you this time offers all usual features – at the first sight. But when we go deeper, we find out that besides a pleasant resolution (5999) and a decent precision (0,5-0,8%) it also offers 60mV ranges – for DC and also AC. Especially in the AC field it´s not that common (at equipment of thice price-level) and moreover – all that we measure in the AC signals can be labeled as TRMS (true RMS). And to all this, also measuring of current starts with a 600uA range (DC aj AC), what means measuring with a 0,1uA resolution.
Probably the last main bonus of UT61D is a possibility of communication with PC via serial port (RS232) and displaying of measured parameters in a simple graphic software.
UT61D handles high and also extra low voltages – [Link]
We are used to seeing oscilloscopes with built-in features such as function generators, DVMs and spectrum analysers but now Keithley have switched the tables and produced a DVM or ‘Graphical Sampling Multimeter’ with a built-in waveform capture/display feature. The DMM7510 has a 5 inch capacitive touchscreen interface displaying measurements to 7½ digit accuracy and a waveform capture capability of 1Msample/s using an 18-bit digitiser.
According to the data sheet the DMM7510 features a low noise input stage with a 32-bit A/D converter giving the instrument DC accuracies that are typically only available with metrology-grade instruments. The instrument has good sensitivity featuring 100 mV, 10 ohm and 10 microamp full scale measurement ranges.
The meter also includes measuring ranges for capacitance, ACV and ACI, temperature (RTD, thermistor and thermo-couple), 2- and 4-wire resistance, dry circuit ohms, period, frequency, diode test and DC voltage ratio. In addition to the touch screen GUI the DMM7510 includes a USB 2.0 port to store test results and screen images, a HELP key, a rotary navigation/control knob and a front/rear input selector button. The front panel buttons are backlit and Keithley include their Test Script Processor system and SCPI programming mode. This allows test scripts to be run directly on the instrument without the need for an external PC.
Keithley 7½ digit touch screen DVM – [Link]
Clamp multimeters are not only practical, but also highly safe at measuring a current. One of them is also the compact Voltcraft VC-521.
Clamp multimeter can be marked as an “old known thing”. AT the same it can be said, that this widely spread type of measuring devices is still more compact and new models are usually able to measure all basic parameters.
From this point of view, the VC-521 can replace a common multimeter, as it´s able to measure voltage, current by means of jaws (even the DC!), frequency, duty cycle, capacity (already from nF), resistance, temperature, diodes and continuity. A useful additional feature is also a non-contact detection of AC voltage (100-600V). User comfort is also increased by functions HOLD and REL. The REL function can serve for a classic measuring but also to null the offset at measuring of DC currents caused by a residual magnetism in the jaws – this can temporarily appear after measuring of high DC currents or also by influence of external magnetic field (magnet, loudspeaker,…).
Plastic lug on one of the jaws is in fact a sensor for non-contact AC voltage detection. This lug also enables easier “separation” of a desired wire from other wires – for example at measuring in a distribution box. Maximum reading is 3999, what´s naturally better than classic „1999″.
“Wireless” measuring is always safer … – [Link]
by Martin Rowe @ edn.com:
The DMM (digital multimeter) is a basic measurement tool for nearly every electrical engineer and many other engineers. With the push to constantly improve power efficiency in electronic designs comes a need to not only measure voltage and current, but to dynamically see them as well. Keithey’s DMM7510 combines a 7½-digit DMM with an 18-bit, 1 Msample/s digitizer, which lets you see measurements both numerically and graphically.
Having the ability to see waveforms lets you uncover problems that used to require an oscilloscope. The DMM7510 also features a 5-in. capacitive touch screen. You can use gestures such as swipes and pinches to sweep though setup menus or zoom in or out of waveforms. I tried it firsthand just prior to today’s product launch, as the short video below shows.
DMM provides numerical and graphical displays – [Link]
Clamp multimeter UT204 measures reliably even in real conditions of nowadays mains supplies and for an affordable price moreover.
UT204 from company UNI-Trend is a near relative to the UT203. multimeter. Already UT203 provides a lot of user comfort and a very pleasant feature – measuring of a DC current without interrupting a measured circuit. However UT204 is different from its “weaker” brother in one essential thing – it enable measuring of a true RMS value of alternating signals (TRMS).
As we know, usual multimeters usually deploy a simple rectifier and an RC cell and they´re calibrated to show an effective value of AC voltage – supposing an ideally sinusoidal shape of a measured variable.
In many cases, a non-TRMS multimeter is fully sufficient, but still more frequently we meet devices, which by their power consumption significantly deform originally sinusoidal shape of a mains line voltage. A vast majority of new devices is equipped with switch-mode power supplies deforming a sinusoid, as they draw current for charging of input capacitors mainly on a top of a sinusoid. This situation is partially better at power supplies with a power factor correction (PFC), but even in these cases it´s never an ideal load. At any difference from an ideal sinusoid the accuracy of a common meter significantly drops down and the error can exceed tens of percents. Similar situation is also at various DC/AC inverters (for example 12VDC/230VAC), whose output is usually only an approximated sinus.
That´s why if exact measurement matters to us, it´s more certain to measure by a device equipped by a TRMS measurement. There are many types with this function on the market, and in a segment of clamp multimeters it´s for example the above mentioned UT204, which moreover offers a lot of other functionality for an excellent price.
Detailed information and comparison of UT203/ UT204 will provide you the UT204 datasheet and the UT204 datasheet and UT203-204 user guide. We keep Uni Trend UT204 as a standard – immediately available item.
UT204 is able to measure DC current and also True RMS – [Link]
2x UT33 – with a manual and also automatic range selection are ideal “reserve” tool for every workplace.
Majority of us already probably has its own favorite multimeter. However, sometimes it happens, that we need to measure two parameters at once (for example voltage and current) and with one device it´s usually not possible… Even though it´s obvious, that it would be ideal to have two multimeters, you didn´t buy it, because you simply don´t want or can´t invest a considerable amount into another tool (maybe even a “top level” one.
That´s why we have for you a tip how to solve this dilemma. It is the multimeter Uni-Trend UT33 and right in two versions:
Both tools feature an excellent price/ performance ratio. For the price of approx. 8-11 Euro they offer measurement of all common parameters, incl. AC (voltage, UT33A also current). UT33A also measures hFE of transistors, UT33C a temperature by a K probe. In many cases a higher resolution of UT33A (3999) can be very beneficial. Decent accuracy, solid construction and exchangeable measuring leads (not hard-wired to a device, as usually in this price-level) belong to another pluses of this series. Naturally, multimeters UT33 are also suitable as a “main” tool for beginning amateurs and students.
Universal multimeters UT33A and UT33C for a special price – [Link]
Energy is transmitted in different ways and one of these ways is electricity. It can appear in many forms and through various phenomena such as lightening or electromagnetic induction, and can be used in transport, electrical appliances, and in the residential and industrial sector, to name but a few examples. Physical magnitudes are derived from electricity such as the electric field, current, and electric potential. The latter two are measured in amps and volts respectively.
In order to measure the previous magnitudes and many others, ingenious devices have been developed, called multimeters, which are the perfect example of the high integrity and versatility of the most modern measuring instruments. They are powerful devices, small in size, but large in their ability to detect and solve electrical failures, measure a large variety of parameters such as current, voltage, capacity, resistance, and they are also equipped with additional functions which allow them to measure temperature, continuity, frequency, carry out diode tests or perform as an oscilloscope. Many multimeters have a USB port and have wireless transfer capacity (Bluetooth), which means that the measurement results can be sent to a PC or computer for later analysis. In addition, many of them are designed in such a way that their screen is removable, so that they can operate in difficult to access areas. Read the rest of this entry »
Dave teardown 3 classic analog multimeters:
EEVblog #634 – Analog Multimeter Teardowns – [Link]
When a tool becomes a legend, usually there must be a good reason for it. This is also the case of Voltcraft mark.
Voltcraft has become legendary as a mark almost “from day to day” when in th year 1982 introduced on the market the first digital multimeter Voltcraft 6010 affordable for wide range of customers (for 139 DM), when other common tools were sold for about 300 DM. Already in the first year over 100 000 pcs were sold. Naturally, only the price wouldn´t cause such attention, but it was remarkable, that this tool offered (at a given price) practically the same functionality as other significantly more expensive tools.
This philosophy of an excellent price/ performance ratio together with technical innovations maintains mark Voltcraft up to day and nowadays multimeters represent somewhat like a golden middle way between usual quality meters and top level professional types, as for the quality and also as for the price. Voltcraft often brings innovations, which can´t be found at other equipment or we only find them after some time …
Despite a very affordable price, we can find at Voltcraft tools some features of top-level equipment, for example:
● optically insulated interface for communication with PC, possibility to combine data from several meters in one window
● robust fuse with a disconnecting ability of 1000V/30kA
● lock against insertion of measuring leads into a device if a rear cover is not closed (at a battery exchange)
● low pass filter (LPF below 1kHz) for interference suppression at measuring of AC voltages
● possibility to measure at a decreased impedance (400 kOhm) to suppress interference
● possibility to measure by a clamp accessory (display shows A, mA)
● they´re available with a calibration certificate (at an extra price)
● majority of types has a max. reading of 5999 or up to 39999
● usually they´re CATIV/600V, CAT III/1000V class
● also available types with a resolution of 0,01 Ohm
● measuring of capacity with 10 pF or even 1 pF resolution
● usage of OLED display (VC890)
In our offer can be found a few types attached below this article. A comprehensive comparison of basic features illustrates attached picture and detailed information ca be found in datasheets at particular types.
Multimeters Voltcraft – above-standard quality for an appropriate price – [Link]