A dimmer adaptable to either two (H, DH) or three (H, N, DH) active wires includes a first full-wave rectifier (D1, D2, D3, D4) across an AC power hot (H) terminal and a dimmer hot (DH) terminal and a second full-wave rectifier (D1, D4, D5, D6) across the AC power hot (H) terminal and an AC power neutral (N) terminal. The dimmer operates in a two-wire configuration by drawing power through a load when a control circuit is not conducting or in a three-wire configuration, when the AC power neutral (N) terminal is connected, by drawing power from AC power hot (H) and AC power neutral (N) terminals. The dimmer operates according to a first set of preset dim levels when current is flowing through the first rectifier and according to a second set of preset dim levels when current is flowing through the second rectifier.