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.

Need another General Meter?
Shop for Comparable Products on our
 used General Meter page

   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 *
Click on Logo for More Prices
*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.

Crest Factor
Crest factor or peak-to-average ratio (PAR) is a measurement of a waveform, calculated from the peak amplitude of the waveform divided by the RMS value of the waveform

Linearity is the relative difference between the displayed power ratio, Dx/D0, and the actual (true) power ratio Px/P0 caused by changing the displayed power level from the reference level, D0, to an arbitrary displayed level, Dx.

Phase Noise
Phase noise is the frequency domain representation of rapid, short-term, random fluctuations in the phase of a waveform, caused by time domain instabilities. Phase noise (L(f)) is typically expressed in units of dBc/Hz, representing the noise power relative to the carrier contained in a 1 Hz bandwidth centered at a certain offsets from the carrier.

Sensitivity is the minimum magnitude of input signal required to produce a specified output signal having a specified signal-to-noise ratio, or other specified criteria.

Please contact us for your KEITHLEY 428 REPAIR and/or KEITHLEY 428 Current Amplifier CALIBRATION

I'm interested in: 
Calibration Type (Select one):

Repair Information:
 Serial Number:

 Is there any physical damage?  
 If yes, describe:

What is the description of the problem?

How/when did the problem start?

 (*) Required Fields    For formal quote please fill in all fields.
From (Email):*
Contact Name:*
Address 1:
Address 2:
State/Territory/Province: *
Zip/Postal Code: