Optimal full scale deflection on analog meters
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Consider you built a volt meter with an analog scale, and chose full-scale deflections of 1, 10, 100 and 1000 V. Then you decided that the gaps were too big, so would add intermediate full scale deflections, so have?
1, x, 10, y, 100, z, 1000 V. What are the optimal values of x, y and z? My gut feeling is that the optimal value of x is sqrt(10) = 3.16, ?because the ratio between 1 and 3.16 is the same as between 3.16 and 10. One would probably round them to? 1, 3, 10, 30, 100, 300 and 1000 V. However, I am not sure about this. I have seen some instruments with FSDs of 1, 2.5, 10, 25, 100, 250, 1000 V. If one assumes that all voltages between 1 and 10 are equally likely to be present, their mean would be 4.5, so scales of? 1, 4.5, 10, 45, 100, 450 and 1000 would be optimal. But I don¡¯t think that¡¯s optimal. I looking at a design where values could be between 0 and 100. The full scale deflections were 20 and 100, which didn¡¯t seem right to me.? Any thoughts? -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@... Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom |
Dr. David Kirkby, Kirkby Microwave Ltd