Precision Voltage Adapter For Low Voltage Measurement

A typical 3 ½ or 4 ½ multimeter can measure voltage in the low mV range and current in the low mA range. Voltage measurement in the µV range and current measurement in the nA range are typically only available in the more expensive lab bench multimeters. In this post, I will show you a simple adapter circuit that can be used for precision voltage measurement down to the µV range. Using this circuit along with the current adapter circuit I discussed earlier you will be able to perform most of the low level measurements with a 3 ½ meter.
Voltage Adapter
This circuit is built around TI’s programmable precision instrumentation amplifier LMP8358. The basic circuit is quite simple and is shown below:
The gain is determined by the DIP switches and the Op-Amp LM358 forms a virtual ground circuit so that voltages of both polarities can be handled. Using both supply rails also has some additional benefits. Because either positive or negative signals can be measured, this circuit is capable of measuring AC voltages with a frequency up to 80kHz at the gain of 1000 or 8MHz with a gain of 10.
The following picture shows the actual circuit built using a protoboard. I used three AA batteries to power it so that the output can swing between -2V and 2V, which ensures high resolution for using with 3 ½ meters (2,000 counts).
For more detail: Precision Voltage Adapter For Low Voltage Measurement

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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