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I'm measuring current consumption of several different handheld devices (calculators, flashlights, etc), at the [lithium] battery. Using a simple multi-meter set to mA, I'm measuring current separately between '+', and separately between '-'. I see some devices which show slightly different readings between '+' and between '-'.

One no-name calculator, for example. When in use, I'm seeing a small difference of -53.2mA at '+' vs -52.8 mA at '-'. After about 5 minutes of inactivity, it automatically turns the display off, and for almost exactly 120 seconds measures -1.57mA drain when measured between '+', and -0.08mA drain when measured between '-' of the battery, then both readings drop to about 0.0 mA. I am assuming it goes to some sort of a deeper sleep mode. But what is the most likely explanation for the discrepancy in measurements?

^{simulate this circuit – Schematic created using CircuitLab}

I'm measuring current consumption of several different handheld devices (calculators, flashlights, etc), at the [lithium] battery. Using a simple Uni-T digital multimeter set to mA, I'm measuring current separately between '+', and separately between '-'. I see some devices which show slightly different readings between '+' and between '-'.

One no-name calculator, for example. When in use, I'm seeing a small difference of -53.2mA at '+' vs -52.8 mA at '-'. After about 5 minutes of inactivity, it automatically turns the display off, and for almost exactly 120 seconds measures -1.57mA drain when measured between '+', and -0.08mA drain when measured between '-' of the battery, then both readings drop to about 0.0 mA. I am assuming it goes to some sort of a deeper sleep mode. But what is the most likely explanation for the discrepancy in measurements?

^{simulate this circuit – Schematic created using CircuitLab}

I'm measuring current consumption of several different handheld devices (calculators, flashlights, etc), at the [lithium] battery. Using a simple multi-meter set to mA, I'm measuring current separately between '+', and separately between '-'. I see some devices which show slightly different readings between '+' and between '-'.

One no-name calculator, for example. When in use, I'm seeing a small difference of -53.2mA at '+' vs -52.8 mA at '-'. After about 5 minutes of inactivity, it automatically turns the display off, and for almost exactly 120 seconds measures -1.57mA drain when measured between '+', and -0.08mA drain when measured between '-' of the battery, then both readings drop to about 0.0 mA. I am assuming it goes to some sort of a deeper sleep mode. But what is the most likely explanation for the discrepancy in measurements?

^{simulate this circuit – Schematic created using CircuitLab}

I'm measuring current consumption of several different handheld devices (calculators, flashlights, etc), at the [lithium] battery. Using a simple multi-meter set to mA, I'm measuring current separately between '+', and separately between '-'. I see some devices which show slightly different readings between '+' and between '-'.

One no-name calculator, for example. When in use, I'm seeing a small difference of -53.2mA at '+' vs -52.8 mA at '-'. After about 5 minutes of inactivity, it automatically turns the display off, and for almost exactly 120 seconds measures -1.57mA drain when measured between '+', and -0.08mA drain when measured between '-' of the battery, then both readings drop to about 0.0 mA. I am assuming it goes to some sort of a deeper sleep mode. But what is the most likely explanation for the discrepancy in measurements?