#TOTD Op-amps (and by extension in-amps) are amazing devices. Recently, when debugging an analog circuit, I noticed that the output of a buffer was measuring half Vdd with the input floating. However, when I tried to measure the voltage at the input I could only read zero. The cool part is the output of the op-amp would also swing to ground when I was reading the input. It turns out the generic op-amp has higher input impedance than my multimeter, which pulled down the input.