# Voltage reading between hand and 3.3V source is only 0.1mV. Why?

I held one multimeter probe to a 3.3V source, the other probe I held in my hand. The voltage measured between these 2 points was around 0.1mV. How is this possible? I expected 3.3V since I thought my hand was a ground?

What I find at least as strange is that when I held one probe in my left hand and one in my right the voltage is larger than the former measure(around 2.3mV!! But it fluctuates much more though)

Is the following correct?

So the multimeter can't pick the real voltage drop up because the total resistance is too high but for some reason related to how the multimeter is built picks up a stable 0.1mV.

Also, the circuit extends from my hand to the floor I'm standing on to the table's legs up to the ground terminal of the device delivering the voltage. The real voltage drop between the two probed points is very small because the resistance of the multimeter dissipates so little energy it hardly drops the voltage.

Suppose the multimeter was a perfect measuring device, given that the larger the resistor, the more energy used by that resistor, and the bigger the voltage drop across that resistor and my body and the rest of the circuit has a very high resistance, the voltage drop between my hand and the ground terminal is actually very large.

• I suggest you get an oscilloscope (AC couple with high gain) and repeat the experiment and you'll see all the noise in real time and as you move the probe and its ground around. It will give you a better feel than just looking at the LSB (least significant bit) errors and noise on a DMM. Depending on how the DMM is sampling and its ADC it can come up with some odd readings in high impedance cases on the DC setting when noise is involved. – user6972 Sep 1 '13 at 19:06