A logarithmic radiation meter is described using as detector, a photomultiplier and scintillation phosphor. A one‐tube feedback circuit varies the voltage applied to the photomultiplier so as to hold its anode current constant for different incident radiation intensities. The voltage applied to the photomultiplier is then a nearly logarithmic measure of the radiation intensity over a range of 104. Circuit details and experimental results are given of a battery‐operated portable model and an ac operated model which incorporates means for correcting the slight compression towards one end of the scale found in the portable model.