ARISTO-Werke Dennert & Pape, Hamburg / Germany       (1935)
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SCALES  of the  ARISTO  POCKET   E L E K T R O   TELEFUNKEN
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Front Side    [  RED ]                            Back Side
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( 0 ...  13 cm Ruler )

U1/U2      X5
A          X2
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B          X2                           S        sin(0.1X)
Neper      ln|U1/U2|                    ST       arc(0.01X)
C          X                            T        tan(0.1X)
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[D]        [X]
dB * 10    lg( |U1/U2|2 )

R E M A R K S :                          No Production Code
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Historical Remarks ...

This Pocket Slide Rule was a gift from  » TELEFUNKEN «  a
company well known for e.g. radio transmitters & receivers.

   Neper   [ N ]   =     ln( U1 / U2 )
   Dezibel [ dB ]  =  10*lg( P1 / P2 )
                   =  10 * lg{ ( U12/R1 ) / ( U22/R2 ) }
                   =  10 * lg{ ( U1 / U2 )2 * R2/R1 }
                   =  20 * lg| U1 / U2 |  with  R1 = R2

     spec.:   0 dB = 1 mW  on  600 Ω  =  0.775 V

     ===>>     1 N = 8.686 dB
              1 dB = 0.1151 N

impressum:
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© C.HAMANN   http://public.BHT-Berlin.de/hamann    09/21/10