Classic non-scientific test.
Get your multimeter.
Positive prove on 3v.
Left thumb on common multimeter probe.
Right finger on ground.
I get 2.962v, but if I test my resistance and do the math, It's much different.
If you're part of the circuit, you're messing up your readings, keep your fingers off the probe tips and circuitry, you're a resistor, capacitor, and noise source all in one.