Using biased, electrical power feedback to an electrical heater, the output signal from a pyroelectric detector is made to follow the waveform of incident electromagnetic radiation. The feedback power is applied to the detector to reduce the rate of change of the detector temperature that would otherwise be caused by the absorbed radiation. The combined signals from the radiation and feedback power produce a response that follows the radiation waveform with a fast rise time and with substantially less droop than previously reported. The high fidelity of the response waveform allows for a substantial simplification of the optical chopper designs and electronics needed to implement electrical calibration. In contrast to previous electrical calibration with pyroelectrics that needed very specialized electronics, with this method a variety instruments can be used for reading pyroelectric signals. The method allows for signal processing that reduces phase noise and yields very accurate radiation power measurements.