Auxiliary Equipment

The Firth Cleveland frequency meter Type FM1015, manufactured by Firth Cleveland Instruments Ltd., Treforest, Pontypridd, Glamorgan, Wales, a member of the Firth Cleveland Group, is a lightweight instrument, designed to measure the frequency of signals having a wide variation in both amplitude and wave‐form over four switched frequency ranges for full‐scale indication of 200 c/s, 2 Kc/s, 20 Kc/s and 200 Kc/s. The instrument may be operated from an internal battery or mains supply, and over each of the frequency ranges stated, the accuracy of indication is within ±2½ per cent of F.S.D. when the input signals have an amplitude within 0·075 and 10 volts r.m.s.