Reviewing the CSI2012L from Circuit

The Circuit Specialists CSI2012L multimeter was evaluated and tested to compare it to other similar DMMs. This unit has a unique “lockout” feature that will prevent the user from inserting the test probes in an incorrect plug. This is ideal for students and novice users since it will prevent fuse blowing caused by incorrect operation.

The purpose of this comparison is to demonstrate the relative accuracy and illustrate the features of this new product. The CSI2012L multimeter has an auto shut down feature that extends battery life when the unit is left powered up. Besides the standard AC and DC measurement modes, it also features Data Hold, and an audible continuity function, as well as diode test and transistor hFE (Gain) measurement and capacitance measurement up to 2000 mF.

The measurements performed were Voltage (AC and DC), current (AC and DC), Resistance, and Capacitance. In addition, the transistor measurement feature was exercised and compared to value obtained from a dedicated transistor tester.

The basic accuracy of the DMM is a nominal 0.8%, which is more than adequate for a general purpose DMM. The unit was tested on the various ranges and found to be well within the published specifications.

One feature of the Circuit Specialists CSI2012L meter that was especially noteworthy is the mechanical lockout feature for the probes. When switching from one measurement mode to another the correct jacks on the meter are opened as required. This prevents the operator from inserting the problems in the wrong jacks when making voltage or current measurements. The accompanying photographs show the three possible configurations of this safety feature. Fig. 1 shows the selector switch set to measure current up to 10 Amps. Note that the COM and 10A jacks are the only ones accessible, the mA and Volts jacks are mechanically locked out to prevent incorrect lest lead insertion. Fig. 2 shows the selector switch set to measure current values in the mA range. Note that the COM and mA jacks are now accessible and that the 10A and Volts jacks are mechanically blocked. Finally Fig. 3 shows the selector switch set to measure Voltage. In this position the COM and Volts jacks are the only accessible jacks and the 10A and mA jacks are blocked. One of the most common mistakes that is made when using a digital multimeter is forgetting to move the test leads from one position to another when switching between current and voltage measurements. If this is done the meter can be damaged or at a minimum, the internal fuse would blow. This mechanical lockout feature prevents this common problem when using a DMM.

The CSI2012L is a low priced but extremely capable measuring device that compares favorably to a much higher priced unit. The mechanical lockout feature makes this unit especially attractive as a starter DMM for students, novices, and technicians.

Click images to enlarge.

Fig 1                                                         Fig 2                                                  Fig 3


George Leger has a Masters in Electrical Engineering from Stanford University, worked in private industry pioneering surface-mount technology and in government research labs for twenty years, published several papers on surface-mount technology, co-authored papers published in national symposiums on accelerator technology, was past president of SMTA and an adjunct professor at the community college level, holds a patent, and is a certified microchip design partner, serving as a consultant to many companies developing electronic circuits.

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