PDA-700 - Electro-Optical Products Current Amplifiers

Electro-Optical Products PDA-700 Overview

The PDA-700 is a low noise, high gain, transimpedance amplifier designed to provide a direct digital readout of the current generated from a photodiode, photomultiplier or other similar current source. Digital selection of a calibration factor in terms of Amp/Watt via the front panel controls permits the unit to display the measurement directly in Watts. The A/W setting may range from 1.0000 to 0.1000. Subsequent current readings are divided by this cal factor when the Amps/Watt control is engaged. A variable bias voltage, ranging from +10V to -10V, may be digitally selected from the front panel and applied in series with the photodiode under test. The background cancellation feature allows offsets from +200% to -200% of the selected full scale range to be added to or subtracted from the input signal. A large liquid crystal display provides a maximum resolution of 1 part in 20,000, thus permitting the detection of very small changes in the variable that is to be measured. the display is also equipped with an LED back-light for reading in a darkened laboratory. An analog output is provided with a 2 volt full-scale signal that is proportional to the maximum display reading of 20,000 counts. Rechargeable batteries isolate the unit from the mains and eliminate the effects of ground loops and/or power line noise. They provide power to the unit for a minimum of 20 hours of operation between charges. The unit may be operated normally while the batteries are charging. The instrument is covered by a standard two year limited warranty. Applications include: serving as a readout for Unity Quantum Efficient Detectors such as those manufactured by Graseby Optronics, characterization of detector dark current, spectral calibration of detectors and use as a sensitive low cost optical power meter.