Custom-Cal has a high success rate in the repair of the KEITHLEY 428. 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 428 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 428   Description / Specification:    
KEITHLEY 428 Current Amplifier

The Keithley 428 Current Amplifier converts fast, small currents to a voltage, which can be easily digitized or displayed by an oscilloscope, wave-form analyzer, or data acquisition system. It uses a sophisticated "feedback current" circuit to achieve both fast rise times and sub-picoamp noise. The gain of the 428 is adjustable in decade increments from 10^3 V/A to 10^11 V/A, with selectable rise times from 2 µs to 300ms. Input and output connections to the 428 are made with BNC connectors. INPUT HI is connected to a programmable ±5V supply, which permits suitable bias voltages to be applied to devices-under-test or current collectors. This eliminates the need for a separate bias supply. Specifications. Input Voltage Burden: <200 µV (18°–28°C) for inputs <100 µA; <10 mV for inputs >= 100 µA; 20 µV/°C temperature coefficient. Input Maximum Overload: 100V on 10^4 to 10^11 V/A ranges; 10 V on 10^3 V/A range. Higher voltage sources must be current limited at 10 mA. Output Range: ±10V, 1 mA; bias voltage off. Output Impedance: <100 ohm DC - 175 kHz. Low Pass Ranges: 10 µs to 300 ms (±25%) in 1, 3, 10 sequence or OFF. Output Attenuation: 12 dB/octave. Gain ×10: Rise time, noise, and input resistance are unchanged when selecting GAIN ×10; gain accuracy and temperature coefficient are degraded by 0.2% and 0.003%/°C respectively. Display: Ten character alphanumeric LED display with normal/dim/off intensity control.


Standard Calibration $295.00 *
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*This is a Web introductory price for one calibration of the KEITHLEY 428. 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.

Averaging is a mathematical process to reduce the variation in a measurement by summing the data points from multiple measurements and dividing by the number of points summed.

Fall Time
Fall time is the time required for the amplitude of a pulse to decrease (fall) from a specified value (usually 90 percent of the peak value exclusive of overshoot or undershoot) to another specified value (usually 10 percent of the maximum value exclusive of overshoot or undershoot).

Noise Density
Noise Density is the amount of noise within a defined bandwidth, usually normalized to 1 Hz.

Resolution Bandwidth (RBW)
Resolution Bandwidth (RBW) is the minimum bandwidth over which you can separate two signals and still see them.

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