When I first saw the Agilent U1253A it immediately reminded me of a trainee electronics technician project that I completed over 30 years ago. The project was to build an LED DVM from a design described in “Practical Electronics”. All this DVM could do was measure DC volts and because of the power hungry LED display it was powered from the mains! However, bright easy to see displays is where the similarity ends as the Agilent U1253A is a state of the art multimeter using the latest organic light emitting diode (OLED) technology. OLEDs are as bright as conventional LEDs but are not as power hungry and far easier to see than LCD displays. It is a pixilated, yellow, display rather than the 7 segment LED / LCD type. This obviously broadens its ability to display more than just basic information.
Unlike my homemade DVM of 30 years ago this unit uses a 7.2 Volt NiMh rechargeable battery but does not have a dedicated charging socket! Instead it cleverly uses the 440mA socket and the common terminal via an external charging adaptor and charger. Presumably the meter is protected if the wrong sockets are used. I did not want to risk using the wrong ones. When a charger is connected it works out if a rechargeable battery is installed or not. If a rechargeable is installed it then cleverly limits the charging time and displays the charge level as it charges. In order to check battery life the DVMs on board programmable menus were utilised. It is possible to change the auto off time to what ever you want up to 99mins or you can just disable this function if so desired. Changing the on board menus is slightly confusing as only the lightest touch of the SAVE button is required to enter the EDIT function. It does not work if you hold it down. In order to recreate the worst possible battery drain every pixel was switched on permanently with the auto time off function disabled. Amazingly the battery lasted for over 3 hours! Incidentally none of the pixels appeared to be damaged.
As well as having the ability to measure the usual parameters such as voltage, current, resistance, capacitance, frequency, diode test etc. it also has its own board 3V peak to peak square-wave frequency generator with a wide range of preset frequencies, from 0.5Hz to 4800kHz. The duty cycle can also be altered through the full range.
It also has a useful manual logging tool where 1000 events can be recorded internally. Unfortunately the RS 232 optical interface cable was not supplied and downloading to a PC could not be tested. By use of an optional external thermocouple, temperature can also be monitored.
Time did not permit testing of all of its functions but the ones that we did functioned very well. All in all a very robust and versatile instrument with a display that can be observed clearly under any light conditions. I would have no hesitation in recommending potential DMM customers to go “back to the future” and to buy this this particular model.