KAHLSICO
INSTRUMENTATION
DIELECTRIC CONSTANT AND LOSS measuring devices; Model D K 06 with frequency range 0.1 t o 12 mega cycles, heterodyne b e a t principle with C R T indicator sensitive t o 10 ~4. Sample holding cells for all nongaseous media a n d accessory cryogenic a p p a r a tus are available. Nondestructive and precise analyses of mixed compounds, moisture determinations, a n d process quality controls are easily a n d rapidly obtained. Model D K 05 h a s fre quency range 0.03 t o 100 kilocycles.
DK 06 M u l t i - D e k a m e t e r
Figure 2. Accessories for the 4 0 1 include a sample test enclosure for measur ing small components (left) and a sample voltage supply
RAPID, DUAL-BEAM SPECTROSCOPE permits absorptive or reflective meas urements in 8.3 millisecond scan t i m e over typical 350 to 700 n m s p e c t r u m with 1 to 5 n m resolution. Fixed wavelength determination available in 0.1 m s . C R T indicator can display 16 spectra for 1 hour. Solid s t a t e electronics a n d d a t a handling p e r m i t operation a t 100 spectra/sec. r a t e s . Photosensor head m a y be used ver tically or horizontally a n d is offset t o facilitate large specimen handling.
Figure 3. Special pH switch adapts the 4 0 1 for precise measurement of pH changes
10 millisecond interval a b s o r p t i o n spectra of blood f i l m u n d e r g o i n g oxygenation
MICR0SUBLIMAT0RS for identifie*. tion and purification of c o m p o u n d s (vacuum t y p e for r a p i d a n d complete separations), as well a s m o t o r i z e d tensiometers, precision t h e r m o m e t e r s , etc. are available.
KAHL SCIENTIFIC INSTRUMENT CORP. 7 3 7 West Main Street El Cajon, Calif. 9 2 0 2 2 2425 Third Avenue New York, Ν. Υ. 10451 Circle No. 38 on Readers' Service Card 174 A
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ANALYTICAL CHEMISTRY
tered and used to drive the indicating meter. A portion of the dc output is applied as negative feedback to cancel the input signal and also to provide very high gain stability, low insulation leakage, and rapid response. Voltage measurements are read directly on the instrument meter. Charge measurements are determined by multiplying the meter reading b y the value of the charge-collecting ca pacitor (2 χ 1 0 - 1 1 farad). C u r r e n t is measured either by determining the rate a t which electrons are collected on the charge collecting capacitor or b y reading the voltage across one of the three built-in, calibrated, high value input resistors. Resistance is measured b y applying a known potential across the unknown resistance and measuring the resulting current.
The 401 electrometer is illustrated a t the top of Figure 1 and is shown con nected to a single-base assembly on which spherical ionization chambers can be mounted. The spherical cham bers are available in volumes ranging from 250 cc to 14,800 cc, suitable for the measurement of soft beta emitters such as carbon-14, tritium, and sulfur35. All active circuits, including the input stage, contain solid state compo nents to ensure maximum reliability, high resistance to shock and vibrations, long instrument life, and negligible mi crophonics. For convenience of opera tion, all normal operating controls, including the input shorting switch are located on the front panel of the main amplifier. A single control converts from current to voltage measurements. For optimum convenience in measuring current, 10 s , 10 1 0 , and 10 12 ohms input resistors and circuitry for switching them by front panel control are in cluded as standard equipment. Also standard are critical damping pro visions for faster response when using high value input resistors. An op tically polished sapphire input insulator is electrically guarded in all operating modes, protected against breakage, and can be removed for cleaning. There is a choice of five recorder or digital voltmeter outputs a t 30 V, 1 V, 100 mV, 25 mV, a n d 10 m V readily ac cessible on the rear panel. Operating power options include 115 or 230 V, 50 to 60 Hz line power, and an ex ternally connected 12 V battery (not supplied) for applications requiring
