Abstract

A new wide-range logarithmic circuit for a light-intensity meter is described. The circuit, consisting only of photoconductors and constant resistors, takes advantage of the inverse power law that the photoconductors obey. The indicator (microammeter) used is of simple linear type: the deflection is proportional to the current. Accordingly, the over-all response is logarithmic in light intensity. An experimental unit covering more than four decades of intensity is described. The same principle may be applied to nuclear radiation meters.

© 1960 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. Photoconductors are particularly desirable for use in compact light-intensity measuring devices because of their high responsivity.
  2. For a discussion of the physics of photoconductors see, for example: A. Rose, RCA Rev. 12, 350 (1951); H. Kallmann and B. Kramer, Phys. Rev. 87, 91 (1952); Proc. IRE 43, (1955); G. F. J. Garlick, Handbuch der Physik (Springer-Verlag, Berlin, 1956), Vol. XIX, p. 316.
    [Crossref]
  3. Superlinear photoconductors are excluded.
  4. Such photoconductors were supplied by the Clairex Company, New York, and from the Physikalische-Technische Werkstätten, Wiesbaden, Germany.
  5. Supplied by the Clairex Company, New York. The Clairex cells are particularly appropriate for compact exposure meters. The average photosensitive area of these cells is about 1 mm×5 mm. Measurements on these Clairex cells indicate that n≃0.5 and is nearly constant from 0.01 to 50 ft-c, that k≃4×104 and that the contacts are ohmic throughout the operating voltage range.
  6. Supplied by the P. Gossen Company, Erlangen, Germany.
  7. The ammeter’s resistance, being in series with the parallel network, will affect the response. If C[in Eq. (9)] is the conductance of the two-element network and Rm is the meter resistance, the total conductance CT is C(1+CRm)−1. Consequently, so long as Rm is small compared with 1/C at high intensities, the logarithmic character of the response is not appreciably changed.
  8. Supplied by the Physikalische-Technische Werkstätten, Wiesbaden, Germany.
  9. R. Frerichs, J. Appl. Phys. 21, 312 (1950).
    [Crossref]
  10. H. Kallmann and R. Warminsky, Ann. Physik 4, 69 (1948).
    [Crossref]
  11. R. Frerichs and R. Warminsky, Naturwissenschaften 33, 251 (1946).
    [Crossref]
  12. F. Lappe, Z. Physik 154, 267 (1959).
    [Crossref]
  13. H. Kallmann and R. Warminsky, Research 2, 389 (1949).
    [PubMed]
  14. R. Hofstadter, Proc. IRE 38, 726 (1950); S. M. Ryvkin, J. Tech. Phys. (U.S.S.R.) 26, 2667 (1956); S. M. Ryvkin and A. V. Airapetyants, J. Tech. Phys. (U.S.S.R.) 27, 106 (1957).
    [Crossref]
  15. Ryvkin, Bogomazov, Konovalenko, and Mateyev, J. Tech. Phys. (U.S.S.R.) 27, 1601 (1957).
  16. Klick, Peake, Cole, Rabin, and Lambe, Nucleonics,  13, 48 (1955).

1959 (1)

F. Lappe, Z. Physik 154, 267 (1959).
[Crossref]

1957 (1)

Ryvkin, Bogomazov, Konovalenko, and Mateyev, J. Tech. Phys. (U.S.S.R.) 27, 1601 (1957).

1955 (1)

Klick, Peake, Cole, Rabin, and Lambe, Nucleonics,  13, 48 (1955).

1951 (1)

For a discussion of the physics of photoconductors see, for example: A. Rose, RCA Rev. 12, 350 (1951); H. Kallmann and B. Kramer, Phys. Rev. 87, 91 (1952); Proc. IRE 43, (1955); G. F. J. Garlick, Handbuch der Physik (Springer-Verlag, Berlin, 1956), Vol. XIX, p. 316.
[Crossref]

1950 (2)

R. Frerichs, J. Appl. Phys. 21, 312 (1950).
[Crossref]

R. Hofstadter, Proc. IRE 38, 726 (1950); S. M. Ryvkin, J. Tech. Phys. (U.S.S.R.) 26, 2667 (1956); S. M. Ryvkin and A. V. Airapetyants, J. Tech. Phys. (U.S.S.R.) 27, 106 (1957).
[Crossref]

1949 (1)

H. Kallmann and R. Warminsky, Research 2, 389 (1949).
[PubMed]

1948 (1)

H. Kallmann and R. Warminsky, Ann. Physik 4, 69 (1948).
[Crossref]

1946 (1)

R. Frerichs and R. Warminsky, Naturwissenschaften 33, 251 (1946).
[Crossref]

Bogomazov,

Ryvkin, Bogomazov, Konovalenko, and Mateyev, J. Tech. Phys. (U.S.S.R.) 27, 1601 (1957).

Cole,

Klick, Peake, Cole, Rabin, and Lambe, Nucleonics,  13, 48 (1955).

Frerichs, R.

R. Frerichs, J. Appl. Phys. 21, 312 (1950).
[Crossref]

R. Frerichs and R. Warminsky, Naturwissenschaften 33, 251 (1946).
[Crossref]

Hofstadter, R.

R. Hofstadter, Proc. IRE 38, 726 (1950); S. M. Ryvkin, J. Tech. Phys. (U.S.S.R.) 26, 2667 (1956); S. M. Ryvkin and A. V. Airapetyants, J. Tech. Phys. (U.S.S.R.) 27, 106 (1957).
[Crossref]

Kallmann, H.

H. Kallmann and R. Warminsky, Research 2, 389 (1949).
[PubMed]

H. Kallmann and R. Warminsky, Ann. Physik 4, 69 (1948).
[Crossref]

Klick,

Klick, Peake, Cole, Rabin, and Lambe, Nucleonics,  13, 48 (1955).

Konovalenko,

Ryvkin, Bogomazov, Konovalenko, and Mateyev, J. Tech. Phys. (U.S.S.R.) 27, 1601 (1957).

Lambe,

Klick, Peake, Cole, Rabin, and Lambe, Nucleonics,  13, 48 (1955).

Lappe, F.

F. Lappe, Z. Physik 154, 267 (1959).
[Crossref]

Mateyev,

Ryvkin, Bogomazov, Konovalenko, and Mateyev, J. Tech. Phys. (U.S.S.R.) 27, 1601 (1957).

Peake,

Klick, Peake, Cole, Rabin, and Lambe, Nucleonics,  13, 48 (1955).

Rabin,

Klick, Peake, Cole, Rabin, and Lambe, Nucleonics,  13, 48 (1955).

Rose, A.

For a discussion of the physics of photoconductors see, for example: A. Rose, RCA Rev. 12, 350 (1951); H. Kallmann and B. Kramer, Phys. Rev. 87, 91 (1952); Proc. IRE 43, (1955); G. F. J. Garlick, Handbuch der Physik (Springer-Verlag, Berlin, 1956), Vol. XIX, p. 316.
[Crossref]

Ryvkin,

Ryvkin, Bogomazov, Konovalenko, and Mateyev, J. Tech. Phys. (U.S.S.R.) 27, 1601 (1957).

Warminsky, R.

H. Kallmann and R. Warminsky, Research 2, 389 (1949).
[PubMed]

H. Kallmann and R. Warminsky, Ann. Physik 4, 69 (1948).
[Crossref]

R. Frerichs and R. Warminsky, Naturwissenschaften 33, 251 (1946).
[Crossref]

Ann. Physik (1)

H. Kallmann and R. Warminsky, Ann. Physik 4, 69 (1948).
[Crossref]

J. Appl. Phys. (1)

R. Frerichs, J. Appl. Phys. 21, 312 (1950).
[Crossref]

J. Tech. Phys. (U.S.S.R.) (1)

Ryvkin, Bogomazov, Konovalenko, and Mateyev, J. Tech. Phys. (U.S.S.R.) 27, 1601 (1957).

Naturwissenschaften (1)

R. Frerichs and R. Warminsky, Naturwissenschaften 33, 251 (1946).
[Crossref]

Nucleonics (1)

Klick, Peake, Cole, Rabin, and Lambe, Nucleonics,  13, 48 (1955).

Proc. IRE (1)

R. Hofstadter, Proc. IRE 38, 726 (1950); S. M. Ryvkin, J. Tech. Phys. (U.S.S.R.) 26, 2667 (1956); S. M. Ryvkin and A. V. Airapetyants, J. Tech. Phys. (U.S.S.R.) 27, 106 (1957).
[Crossref]

RCA Rev. (1)

For a discussion of the physics of photoconductors see, for example: A. Rose, RCA Rev. 12, 350 (1951); H. Kallmann and B. Kramer, Phys. Rev. 87, 91 (1952); Proc. IRE 43, (1955); G. F. J. Garlick, Handbuch der Physik (Springer-Verlag, Berlin, 1956), Vol. XIX, p. 316.
[Crossref]

Research (1)

H. Kallmann and R. Warminsky, Research 2, 389 (1949).
[PubMed]

Z. Physik (1)

F. Lappe, Z. Physik 154, 267 (1959).
[Crossref]

Other (7)

Photoconductors are particularly desirable for use in compact light-intensity measuring devices because of their high responsivity.

Superlinear photoconductors are excluded.

Such photoconductors were supplied by the Clairex Company, New York, and from the Physikalische-Technische Werkstätten, Wiesbaden, Germany.

Supplied by the Clairex Company, New York. The Clairex cells are particularly appropriate for compact exposure meters. The average photosensitive area of these cells is about 1 mm×5 mm. Measurements on these Clairex cells indicate that n≃0.5 and is nearly constant from 0.01 to 50 ft-c, that k≃4×104 and that the contacts are ohmic throughout the operating voltage range.

Supplied by the P. Gossen Company, Erlangen, Germany.

The ammeter’s resistance, being in series with the parallel network, will affect the response. If C[in Eq. (9)] is the conductance of the two-element network and Rm is the meter resistance, the total conductance CT is C(1+CRm)−1. Consequently, so long as Rm is small compared with 1/C at high intensities, the logarithmic character of the response is not appreciably changed.

Supplied by the Physikalische-Technische Werkstätten, Wiesbaden, Germany.

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (3)

Fig. 1
Fig. 1

Conductance (in units of 1/b1) as a function of exciting intensity (in units of k1/b1). These curves were computed from Eq. (29) with n=1 for λ2I2/I1=10, 102, and 103. When =1/3, the ratio ϕ is equal to 10 as indicated on the graph.

Fig. 2
Fig. 2

Conductance (in units of 1/b1) as a function of exciting intensity (in units of (k1/b1)2). These curves were computed from Eq. (9) with n=0.5 for λ 2 ( I 2 / I 1 ) 1 2 = 10, 102, and 103. When =1/3, the ratio ϕ is equal to 100 as indicated on the graph.

Fig. 3
Fig. 3

Angular deflection of microammeter (in arbitrary units) as a function of exciting intensity (in ft-c). This is the response curve of the light-intensity meter discussed in the text.

Equations (11)

Equations on this page are rendered with MathJax. Learn more.

P = k 1 / I n ,
C 1 = 1 b 1 [ 1 1 + ( k 1 / b 1 ) I - n ] .
d C 1 = S 1 ( I ) ( d I / I ) .
S 1 ( I ) = ( n k 1 / b 1 2 ) [ I n / ( I n + k 1 / b 1 ) 2 ] .
I I 1 = ( k 1 / b 1 ) 1 / n ,
S 1 ( I 1 ) = n / 4 b 1 ,
S 1 ( ϕ I 1 ) / S 1 ( I 1 ) = 4 ϕ n / ( 1 + ϕ n ) 2 1 ,
I I 2 = ( k 2 / k 1 ) 1 / n I 1 .
C = ( 1 / b 1 ) { 1 / [ 1 + ( k 1 / b 1 ) I - n ] + 1 / [ 1 + λ 2 ( k 1 / b 1 ) I - n ] } ,
S ( I ) = ( n k 1 / b 1 2 ) [ I n / ( I n + k 1 / b 1 ) 2 ] + ( n k 1 / b 2 2 ) [ λ 2 I n / ( I n + λ 2 k 1 / b 2 ) 2 ] ,
R = b 1 1 1 + ( b 1 / k 1 ) I n .