Kerry writes: I have just completed a project for accurate milliohm range resistance measurements. The details are on my blog . I’d love to share this with your readers.
To effectively measure small resistance values in the milliohm range, we need to accurately measure the current flowing through and at the same time accurately capture the minute voltage drop across the terminals.
To accurately measure small voltages, one can use a programmable-gain precision instrumentation operational amplifier such as National Semiconductor‘s LMP8358. While you can use other op-amps with varies gains, one of the key benefits of using a programmable-gain gain precision instrumentation op-amp is that there is no need to match the gain setting resistors. LMP8358′s gain can be programmatically set to 10, 20, 50, 100, 200, 500 and 1000, which is superb for amplifing the millivolts voltage drop.
Thanks Kerry! Via the contact form.