• Measures current down to 1pA
• All solid state and IC design
• Very low offset current

Introduction  

This is a very versatile multipurpose equipment for the measurement of low dc currents. It has 6 decade ranges with 100% over-ranging from 10-9A to 10-4A. For the ease, readings are directly obtained on a 3½ digit DPM.

The instrument uses a well designed precision FET input electrometer operational amplifier AD549, which offers the lowest input bias currents (50fA with 10fA ±5V supplies) available in any standard operational amplifier. The excellent characteristics of AD549, ultra low bias current, low offset voltage, low drift and low noise have been fully utilized to obtain best results in the present picoammeter. The first operational amplifier AD549 is used in low level current to voltage configuration and the output has been directly read on a 3½ digit panel meter. The instrument is capable of accepting either polarity of the input current. Well regulated power supplies are incorporated to use the instrument upto 10% changes in a.c. main’s voltage

Applications

• Current from Photomultiplier tubes, Photometers etc.
• Leakage currents in solid state devices.
• FET gate and tube grid-voltage without loading errors
• Current through very high resistance’s in conjunction with a power supply
• Potentials across semiconductors, piezoelectric system & pH/plon sensitive electrodes
• Electrical conductivity of air
• Very low current oxygen sensors

Specifications