The power‐per‐line analyzer is an instrument designed to provide a continuous real‐time display of any laser spectra on an oscilloscope. In this article the HF and DF laser version of this instrument is described. A new continuous drive and electronic calibration method are used, eliminating the need for mechanical and optical recalibration. The wavelength is proportional to the dc voltage generated by the scanner’s angular position transducer, which drives thexaxis of an oscilloscope. The relative line intensity is proportional to the dc voltage generated by a pyroelectric detector and drives theyaxis of the oscilloscope. The wavelength calibration accuracy of the final instrument is 0.8% full scale, and the resolution is 2 nm.