| 摘要 |
445,960. Photographic exposuremeters. MACADIE, H. S., and AUTOMATIC COIL WINDER & ELECTRICAL EQUIPMENT CO., Ltd., Winder House, Douglas Street, London. Dec. 12, 1934, No. 35701. [Class 98 (i)] In a photo-electric photographic exposuremeter, the electrical measuring instrument is shunted by a potentiometer and a variable resistance is included in the lead from the photo-electric cell to the potentiometer contact, the contacts of the variable resistance and the potentiometer being mechanically connected and operable by an adjustable setting member. As shown, in a recess 8 in a casing 1 is a photo-electric cell 4. An aperture 9 closed by a glass cover 9<1> limits the angle of incident light. Below the cell 4 is a microammeter 10 having a pointer 13 moving over a scale 15. One electrode 6 of the cell 4 is connected to the meter 10, and the other electrode 5 is connected to a rheostat 16. The contact arm 18 of the rheostat 16 and the contact arm 19 of the potentiometer 17 are carried on a spindle 20 having a knob 21 with an arrow 22. Mounted frictiontight on the knob 21 is a disc 23 provided with emulsion speed graduations 24 and three arrows 25, 26, 27. The casing 1 has lens-aperture graduations 28. The scale 15 has three exposure-time graduations 29, 30 and 31, corresponding to the arrows 25, 26, 27. The potentiometer 17 is graded so that the graduations are equally spaced. The scales A-G on the scale 15 and the disc are for use with a kinematograph camera working at the standard shutter-speed. |
