In a typical LArTPC, each wire in each anode plane is part of an RC circuit, with the wire itself located between the resistor and capacitor. The other end of the resistor is wired to a bias voltage, and the other end of the capacitor is wired to the front-end electronics. The front-end electronics amplify and digitize the current in the circuit. This amplified and digitized current as a function of time is the "signal" that is passed to the event reconstruction.