The Tektronix DMM4050 has all the usual features you would expect in a high accuracy bench-top multimeter.
The main modes are DC voltage and current, AC voltage and current (with true RMS), resistance (2- and 4-wire), continuity, diode testing, capacitance and temperature. Temperature measurement is via RTD (resistance temperature detector) only and can be use 2-wire or 4-wire sensing.
The unit measures 225mm wide, 330mm deep and sits 150mm above the bench surface when using the integrated carrying handle as a tilting bail (which provides two different angles). It comes with a pair of high quality needle probes, a power cable, an RS-232-to-USB cable and two CDs with documentation and software.
A calibration certificate is provided along with a booklet that contains installation and safety instructions, as well as listing the accuracy figures.
The basic DC voltage precision is 0.0024% over one year; other modes feature similarly excellent figures. Maximum DC voltage resolution is down to 100nV and DC current to 100pA.
Display, inputs & controls
One of the more outstanding features of this unit is the display. It is a wide-format cyan-on-black graphic LCD which is easily visible from any angle. There are three brightness settings available.
Having a graphic (dot matrix) display means that the format can change depending on the mode. For example, a larger font is used when taking a single measurement compared to dual measurement mode, making the display easier to read. The display also permits graphical features such as the trend plot and histogram.
In addition to the six banana sockets on the front, there are five on the back; the low current sense terminal is duplicated but the 10A terminal is not. Two buttons on the front panel switch between the two sets. This could be used for several purposes, eg, to switch between different sets of probes or for connection to an external test interface with less clutter.
Also on the rear panel are the external trigger terminal block, the Ethernet, RS-232 serial and GPIB (General Purpose Interface Bus) ports, the IEC power connector and the power switch.
All functions (including power on/off) are easy to access via the front panel buttons. The interface response is instant – the only time there is a noticeable delay is the first time the unit is turned on after being connected to mains power.