The model 603 Electrometer Amplifier is a high gain amplifier
and voltmeter for the frequency range of dc to 50 kilocycles.
Its outstanding characteristics are an input impedance of
greater than lO¹⁴ ohms shunted by 10 micromicrofarads, a grid
current of less than 5 x 10⁻¹⁴ amperes, a maximum full scale
sensitivity of 2.5 millivolts, differential input, low drift
and a remote probe containing the first stage electrometer
tubes. The remote probe allows the input grids to be located
as far as 24 feet from the main amplifier. By employing this
feature the input capacitance may be kept to a minimum so that
it is possible to achieve fast voltage and current measurements
in high impedance circuits., Current measurements, either differential
or single-ended are made by inserting high megohm
resistors in the place provided in the remote probe.
The output capability of the Model 603 is 10 volts single
ended or 20 volts pushpull at a maximum current of 10 milliamperes.
The output is therefore suitable for driving milliampere