The present embodiments relate to a local coil for a magnetic resonance tomography system. The local coil includes a preamplifier for amplification of a signal received by the local coil from an examination object in a receive phase of the local coil. The local coil also includes a detuning device for detuning the local coil in a transmit phase of the local coil, and a rectification device for supplying voltage to the preamplifier.