The KEITHLEY 238 is currently in stock and available for purchase on our  Sales Page
It is also available for immediate rental.
Custom-Cal has a high success rate in the repair of the KEITHLEY 238. A calibration by Custom-Cal is performed by engineers with extensive OEM experience. We have the expertise and the necessary standards to perform the KEITHLEY 238 Calibration, onsite calibration may be available. We specialize in quick turnaround times and we can handle expedited deliveries upon request.

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   KEITHLEY 238   Description / Specification:    
KEITHLEY 238 High-Current Source-Measure Unit

The Keithley 238 Source-Measure Unit (SMU) is a fully programmable instrument, capable of sourcing and measuring voltage or current simultaneously. It is really four instruments in one: voltage source, current source, voltage measure and current measure. The Keithley 238 offers a decade enhancement in current source and measure (IA). In this higher current range, voltage source and measure is 15 V maximum. It will measure very small currents and voltages. With current sensitivity of 10 fA, measurement capabilities are equal to those of an electrometer. Selectable integration and the filtering of multiple measurements enhances sensitivity for demanding applications. Both source voltages and source currents settle to specified accuracy in as little as 500 µs. Programmable delay and fast, integrating measurement capability can provide coordinated source-measure times of 1 ms. Specifications. Voltage Source range: ±1.5000 V (step 100 µV), ±15.000 V (step 1 mV), ±110.00 V (step 10 mV). Voltage Measure range: ±1.5000 V (resolution 10 µV), ±15.000 V (resolution 100 µV), ±110.00 V (resolution 1 mV). Current Source minimum range: ±1.0000 nA (step 100 fA). Current Source maximum range: ±1.0000 A (step 100 µA). Current Measure minimum range: ±1.0000 nA (resolution 10 fA). Current Measure maximum range: ±1.0000 A (resolution 10 µA). Wideband Noise: 0.1 to 20M Hz, 8 mV p-p typical. Overshoot: <0.01 % (100 V step, 10 mA range). Settling Time: <500 µs to 0.01 % (110 V step, 10 mA range). Remote Sense: Corrects for up to 2V drop in each output lead. Maximum 1 k-ohm per sense lead for rated accuracy. Residual output resistance (as a voltage source) is 0.5 ohm.


Standard Calibration $265.00 *
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*This is a Web introductory price for one calibration of the KEITHLEY 238. Price does not in most cases include measurement performance data. Pricing does include NIST traceable calibration and issue of a calibration certificate and calibration label. Pricing may vary slightly due to volume and location of laboratory supporting calibration. Volume pricing may apply. On-site fees may apply depending on logistics, location and volume of work to be completed during the visit.

Related Bench Equipment Terms and Definitions. For a complete list go to our  Terms and Definitions Page.

dBc (decibels relative to the carrier) is the power ratio of a signal to a carrier signal, expressed in decibels. If the dBc figure is positive, then the relative signal strength is greater than the carrier signal strength. If the dBc figure is negative, then the relative signal strength is less than carrier signal strength.

Load Regulation
Load regulation is the capability to maintain a constant voltage (or current) level on the output channel of a power supply despite changes in the supply's load (such as a change in resistance value connected across the supply output).

Power Linearity
When changing the power level and measuring the differences (in dB) between actual and displayed power levels, the power linearity is ± half the span (in dB) between the maximum and the minimum value of all differences.

Settling Time
Settling time of an output device is the time elapsed from the application of an ideal instantaneous step input to the time at which the amplifier output has entered and remained within a specified error band, usually symmetrical about the final value.

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