My ammeter is produces pretty inconsistent pitches, meaning that the chain must be speeding up and slowing down: it makes a “Whaaw-Whaaw-Whaaw” sound. This makes it a little hard to judge circuits that are supposed to be higher or lower. (This happens even on the simplest circuit, with just a resistor and an ammeter.) On the other hand, the voltmeter reads a pretty consistent output of 6V, with no visible wobble; I know this is inconsistent. Has anyone else encountered this?
It’s not necessary an inconsistent input speed. If the black disc is not flat, the needle might not be touching on the whole surface, which gives the same result.