When most people think of a digital radon detector they tend to think of a piece of radon test equipment used by a measurement professional. This type of digital radon detector is typically used during a radon inspection that is being conducted as part of a home sale.
A continuous radon monitor (CRM) is an active radon monitor. The CRM is electronic and therefore requires some sort of power to operate. It can get its power either from a standard AC wall outlet or from batteries.