We present an alternating current (ac) circuit based on a misoriented bilayer graphene device for analog and digital phase detection. We exploit the ambipolar nature of the transfer characteristics of a misoriented bilayer graphene transistor. The transistor action here is realized using an electrochemical gate integrated into a solid polymer electrolyte layer. This unique combination provides a voltage gain close to unity under ambient conditions, which is one order of magnitude higher than that attainable in back-gated devices. The achieved gain provides sufficient sensitivity to detect phase differences between pairs of analog or digital signals. (C) 2011 American Institute of Physics. [doi:10.1063/1.3615247]