Equipment information

Keithley 604 Analog multimeter
Manufacturer:
Model:
604
Date:
1974
Category:
Group:
Description:
DIFFERENTIAL ELECTROMETER AMPLIFIER

Information

The Keithley model 604 Differential Electrometer Amplifier is a completely solid-state instrument that car. be used by itself single-endedly or differentially either as an Amplifier or a millivoltmeter. b, when used in conjunction with the Model 6041 Differential Current Shunt the model 604 becomes a single-ended or differential picoammeter. Single-ended and differential current measurements from 10⁻⁶ to 10⁻¹⁴ ampere can be made with this setup. Also , high megohm resistors may be installed within the Modal 604 to allow shunt picoammeter operation. model 604 FEATURES a. As an amplifier, the model 604 will operate over a bandwidth from do to 50 kHz or greater with six select able 3-dB points from 30 kz to 100 Hz, Thus, the signal-to-noise ratio may be optimised for a particular application. b. Th® Electrometer Amplifier has an input resistance of greater than 10^-4 ohms shunted by less than 5 picofarads in the unguarded position, that allows high impedance measurement to be made easily. When in the guarded position the input impedance is shunted by less than 1 picofarad, c. Low offset current - less than 2 x 10⁻¹⁴ ampere - minimizes zero offset with high source resistance and permits maximum resolution when measuring current > d. A choice of outputs which can be used simultaneously or singly is available, Each input of the model 604 has' a unity gain output, which has 3.50 ppm accuracy, This allows the model 604 to be used as a preamplifier with differential or digital voltmeters fox precise, measurements. Also, these outputs can be fed into an X-Y recorder for recording data from high impedance sources. When desired, the unity--gain outputs can be monitored for absolute values while recordings are made from the Amplifier output. e. All outputs are short-circuit proof, and output noise referred to the input is nearly constant regardless of the gain, f. The guarding capability of the Model 504 allows fast measurements from high resistance sources, by eliminating' the effects of cable capacitance and leakage. To conveniently facilitate these measurements, the Model 6301 Guarded Probe can be used to connect the source to the Model 604 in the guarded mode. The guard feature is switch selectable. g. Another outstanding feature of the Keithley Modal 604 is its zero stability. Signals can be monitored over weeks without constant rezeroingg, zero drift of the Amplifier is less than 4 millivolts per week; zero offset due to temperature changes is less than 300 microvolts per °C, Zero shift duo to mechanical shock or vibration is negligible. h. Overloads up to ±400 volts will not damage the 604 Amplifier, and recovery is almost immediate. A unique circuit provides protection while maintaining the favorable features of the MOS FET input, i. As another convenience feature, the model 604 provides a vary stable ±1 volt suppression on any range. Variations as small as 1 millivolt in a 1-volt signal can he displayed full scale. j. Variations in line voltages from 105 to 125 volts cause no apparent change even on the most sensitive range. Line frequency noise is practically eliminated from the Modal 604 output. 1~3 . MODEL 6041. The Model 6041 Differential Current Shunt is an accessory specifically designed to convert the Model 604 Amplifier into a single-ended or differential multirange picoammeter. a. The driven guard enables the model 604 Amplifier and the Model 6041 Shunt combination to obtain fast response in current measurements, Input capacitance at the end of a 10-foot cable is maintained at 1 picofarad in the guarded mode. As a result, rise, times of 0,5 millisecond are possible with 10⁻¹¹ ampere input signals. Guarding is maintained through the Model 6041 by the use of triaxial input connectors and total guarding within the Shunt itself. b. For those applications where maximum signal-to™noise ratio is more desirable than fast response, the Model 604 can be used in its unguarded mode, Noise will be as low as 2 x 10⁻¹⁵ ampere using a 10¹¹ ohm resistor. However, rise times are much longer than when the Modal 604 is in its guarded mode. Regardless of mode, the high frequency cut-off can be used to reduce noise at the higher frequencies , c. For those cases where a limited current span is to be monitored, a pair of high megohm resistors, available as the Model 6033, can be mounted internally within the model 604, Although this method limits the current span to only four decades, it does slightly Improve both the noise and the rise time -characteristics over that obtainable with the multi-range Model 6041 Currant Shunt. The compromise between noise and rise time still must be made by choosing the guarded or unguarded mode. d. Low offset current minimizes zero offset with high source resistance, permitting maximum resolution when measuring current.

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Service and User Manual
Manual Type:
Service and User Manual
Pages:
42
Size:
2.96 Mbytes (3105446 Bytes)
Language:
english
Revision:
Manual-ID:
Date:
01 January 1977
Quality:
Scanned document, reading partly badly, partly not readable.
Upload date:
24 August 2018
MD5:
16bccdfc87c4c54e562b39ac3159452e
Downloads:
388

Information

SPECIFICATIONS ... , * iv 1. GENERAL DESCRIPTION. . , . , ... , , . . . 1 2. OPERATION. ... ... 3 3. CIRCUIT DESCRIPTION ... , ... H 4. MAINTENANCE. ... . 13 5. ACCESSORIES. ... ,25 6. REPLACEABLE PARTS, , . . . ... 27 SCHEMATICS ... 36

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Service and User Manual
Manual Type:
Service and User Manual
Pages:
42
Size:
2.26 Mbytes (2370877 Bytes)
Language:
english
Revision:
Manual-ID:
Date:
Quality:
Scanned document, reading partly badly, partly not readable.
Upload date:
13 January 2013
MD5:
3ff2f5b97a1f3b069d722e28c8e8955c
Downloads:
1294

Information

SPECIFICATIONS ... iv 1. GENERAL DISCRIPTION. ... 1 2. OPERATION.. ... 3 3. CIRCUIT DESCRIPTION. ... 11 4. MAINTENANCE ... 13 5. Accessories. ... 25 6. REPLACEABLE PARTS. ... 27 SCHEMATICS ... 36

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