D.C. NANOVOLTMETER MODEL N11
The EM DC Nanovoltmeter model N11 is the result of years of development in the measurement of very low level DC potential. All the experience gained from the EM range of Nanovoltmeters has gone into the design of the N11.
Special care has been taken to ensure that the input stage causes the least possible disturbance to the subject being measured, and the N11 is designed to operate in sensitive circuits at very low levels. With a little care, it is possible to resolve levels of 100 picovolts, with an input impedance which increases to over 1000 Mohm with time. If the N11 is used in conjunction with a digital voltmeter, 100 picovolt bits may be displayed with a minimum of flicker. The instrument is also designed to have a high degree of linearity.
One of the very important features of the N11 is its ability to measure sources with a wide range of impedance, by following the source 'Johnson' noise characteristic closely from 10 ohms to over 100K ohms. This means that the N11, while remaining at room temperature, may be used efficiently to measure a source at helium temperature, and even at helium 3 temperature for some measurements. (See the graph of noise voltage against source resistance).
The excellent stability of this instrument makes it ideal for long term drift measurements, and it may be connected to a recorder and left unattended for long periods.
The six position low pass filter gives the operator control over the response time and reduction of noise from the circuit being measured.
A calibrated offset voltage control is provided, with an eleven position multiplier switch, giving a maximum back-off capability of plus and minus one millivolt. This can be used to measure small changes in comparatively large signals. the level of input which can be offset on any range will be limited only by the resolution of the calibrated potentiometer, i.e. about 0.01%.
The pure copper input terminals ensure that the very high thermal stability of the input amplifier is maintained, and also that connection to the instrument may be made easily.
There are two outputs at the rear of the instrument, one direct and the other isolated. When a high linearity is required, the direct output should be used, if possible, although the isolator also has a good linearity.
The N11 is battery operated from internal chargeable batteries and so has the advantage of complete isolation. This instrument is engineered to a very high standard and comes complete with a plug on terminal shield.
SPECIFICATION DC NANOVOLTMETER MODEL N11
Response Time Constant
Series Mode Rejection
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