Patent ID: 8567897

Claim:
A circuit substrate electrically connectable to a plurality of apparatus-side terminals of a printer, the circuit substrate comprising: a storage device; at least one first terminal connected to the storage device; at least one second terminal to which voltage higher than voltage which is applied to the first terminal is applied; and at least one third terminal, wherein the third terminal is disposed adjacent to the first terminal and the second terminal on the substrate surface of the circuit substrate, the third terminal is connected to an overvoltage detection section provided in the printer when the circuit substrate is connected to the plurality of apparatus-side terminals of the printer, and is used to detect overvoltage which is applied to the third terminal, and a convex portion is provided on the substrate surface between the first terminal and the second terminal, whereby in a case where a liquid droplet has been attached to the second terminal, the liquid droplet easily spreads from the second terminal to the third terminal to cause an overvoltage condition to be detected, rather than the liquid droplet spreading from the second terminal to the first terminal.