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N11型EM直流毫微電壓計是對極低功率直流電位測量多年研究的結果。取自于多種EM毫微電壓計的經(jīng)驗最終促成了N11的設計。

須采取特別的措施，確保輸入級對測量的主體造成的干擾最小。根據設計，N11是在極低功率的敏感電路中運行。無(wú)需過(guò)多照看，在輸入阻抗提升至1000MΩ時(shí)，有可能化解1×10-4瓦特的層次。如果N11與數字電壓計共同使用，就可展示1×10-4伏特比特，并且保持閃爍程度最小。此外，根據設計，這一工具還擁有很高的線(xiàn)性。

N11型EM直流毫微電壓計能在遵循電源“約翰遜”噪聲特性的情況下，在10Ω到100000Ω的范圍內，且在范圍寬廣的電阻條件下對電源進(jìn)行衡量，這是其諸多重要特點(diǎn)之一。這意味著(zhù)N11，在室溫條件下，可以被有效的用來(lái)測量氮溫度中的電源，即使在氮3溫度情況下開(kāi)展某些測量。（參見(jiàn)電源電阻噪聲電壓圖）。

該儀器卓越的穩定性使其成為長(cháng)期偏移測量的理想工具，它還能被連接至記錄器上，也可長(cháng)期無(wú)人值守。

操作人員可以借助6位低通濾波器對響應時(shí)間實(shí)施控制，并降低受到測量的電路噪聲。

具備11個(gè)點(diǎn)位的多功能開(kāi)關(guān)，具備刻度補償電壓控制功能，擁有正負1毫伏的回退能力�？蓪⑵溆糜诤饬肯鄬�較大信號中的較小變化，在任何范圍內對輸入等級的補償將得到刻度電位計的補償，補償率大約為0.01%。

純銅輸入終端確�？梢詫�輸入放大器保持很高的熱穩定性，同時(shí)能夠較為便利的連接至該儀器上。

在儀器尾部由兩個(gè)輸出，一個(gè)是直接的輸出，另一個(gè)是隔離的輸出。雖然隔離器同時(shí)也具備良好的線(xiàn)性，但是當需要較高的線(xiàn)性時(shí)，將使用直接輸出，N11內裝有可置換電池，因此可對其進(jìn)行徹底隔離。對這一儀器進(jìn)行工程調教，使其保持較高的標準，并與終端護罩上的插頭融為一體。

The EM DC Nanovoltmeter model N11 isthe result of years of development in the measurement of very low level DCpotential. All the experience gained from the EM range of Nanovoltmeters hasgone into the design of the N11.

Special care has been taken to ensurethat the input stage causes the least possible disturbance to the subject beingmeasured, and the N11 is designed to operate in sensitive circuits at very lowlevels. With a little care, it is possible to resolve levels of 100picovolts, 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 bitsmay be displayed with a minimum of flicker. The instrument is also designed tohave a high degree of linearity.

One of the very important features ofthe N11 is its ability to measure sources with a wide range of impedance, byfollowing the source 'Johnson' noise characteristic closely from 10 ohms toover 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 athelium 3 temperature for some measurements. (See the graph of noise voltageagainst source resistance).

The excellent stability of thisinstrument makes it ideal for long term drift measurements, and it may beconnected to a recorder and left unattended for long periods.

The six position low pass filtergives the operator control over the response time and reduction of noise fromthe circuit being measured.

A calibrated offset voltage controlis provided, with an eleven position multiplier switch, giving a maximumback-off capability of plus and minus one millivolt. This can be used tomeasure small changes in comparatively large signals. the level of input whichcan be offset on any range will be limited only by the resolution of thecalibrated potentiometer, i.e. about 0.01%.

The pure copper input terminalsensure that the very high thermal stability of the input amplifier ismaintained, and also that connection to the instrument may be made easily.

There are two outputs at the rear ofthe instrument, one direct and the other isolated. When a high linearity isrequired, the direct output should be used, if possible, although the isolatoralso has a good linearity.

The N11 is battery operated frominternal chargeable batteries and so has the advantage of complete isolation.This instrument is engineered to a very high standard and comes complete with aplug on terminal shield.

范圍
輸入范圍的1： 12倍， ± 10nV fsd---- ± 3mV fsd。
輸入范圍的2： 12倍， ± 10mV fsd---- ± 1KV fsd。

Range
Input 1. 12 ranges. +/- 10nV fsd to +/- 3mV fsd
Input 2. 12 ranges. +/- 10mV fsd to +/- 1KV fsd

精確度
直接輸出： ± 0.2%
隔離輸出： ± 0.5%
儀器： ± 1.5%

Accuracy
Direct Output. +/- 0.2%
Isolated Output. +/- 0.5%
Meter. +/- 1.5%

線(xiàn)性
直接輸出優(yōu)于100ppm

Linearity
Direct output better than 100 ppm

零度偏移
優(yōu)于每攝氏度500pV.

Zero Drift
Better than 500pV per degree C.

噪聲同等噪聲阻抗大約為10Ω。噪聲電壓取決于濾波器設置，即：濾波時(shí)間為10秒常數，在輸入短路的情況下，創(chuàng )造的噪聲Vp-p大約為250×10-6V。

Noise
Equivalent noise resistance approximately 10 ohms. Noise voltage dependson filter setting, e.g. filter time constant 10 seconds gives peak to peaknoise voltage of approximately 250 picovolts with the input short circuited.

電源電阻
電源電阻低于10Ω，儀器噪聲穩定的降低至0Ω。隨著(zhù)電源電阻從10Ω上升至數百Ω，儀器細微的提升了電源噪聲。在高于100kΩ的情況下，儀器噪聲以電源電阻提升10進(jìn)制的20dB。N11運行的范圍上限高達1MΩ。

Source Resistance
With a source resistance of less than 10 ohms,the instrument noise is substantially constant down to zero ohms. With sourceresistance from 10 ohms to a few hundred K ohms, the instrument addsinsignificantly to the source noise. Above 100K ohms the instrument noiseincreases at about 20dB per decade of source resistance. The N11 will operatewith sources up to about 1 M ohm.

解析度
極大濾子情況下，1×10-4V。

Resolution
100 picovolts with maximum filter.

輸入阻抗
輸入1：高于30MΩ，階躍輸入后3秒，隨著(zhù)時(shí)間推移上升至1GΩ。

輸入2:10 MΩ

Input Impedance
Input 1. Greater than 30 M ohm, 3 seconds aftera step input, increasing with time to over 1 G ohm.
Input 2. 10 M ohm

補償電流
可在前端面板上調整至0。溫度系數優(yōu)于1pA/℃。

Offset Current
Adjustable to zero at the front panel.Temperature coefficient better than 1pA per degree C.

響應時(shí)間常數
取決于濾波器的設置和范圍。最低250毫秒，最大40秒。

Response Time Constant
Depends on setting of filter and range. Minimum.250 milliseconds. Maximum. 40 seconds.

濾波器
位于前端面板的開(kāi)關(guān)控制的低通量濾波器上的6個(gè)點(diǎn)位。

Filter
Six position low pass filter operated by aswitch on the front panel.

補償
10刻度電位計，刻度范圍為0-1000，帶有11個(gè)電開(kāi)關(guān)，最大補償為正負100nV, 1uV, 10uV, 100uV, 1mV以及1個(gè)0位。解析度：優(yōu)于0.01%。精確度：優(yōu)于0.5%。

Offset
10 turn potentiometer calibrated 0-1000 witheleven position switch giving maximum offsets of plus and minus 100nV, 1uV,10uV, 100uV, 1mV and a '0' position. Resolution. Better than 0.01%. Accuracy.Better than 0.5%.

串聯(lián)方式抑制
在50Hz時(shí)大于80dB。

Series Mode Rejection
Greater than 80dB at 50Hz.

輸出
直接和隔離的輸出為滿(mǎn)刻度偏移設定了±1V的范圍。放大器增益等同于設定的伏特范圍。

Outputs
Direct and isolated outputs give plus and minus1V for full scale deflection. Amplifier gain equals the reciprocal of the rangesetting in volts.

隔離
機箱輸入或輸出。大于100GΩ。

Isolation
Input to case or output. Greater than 100G ohm.

連接器
輸入1：EM低熱電勢終端。在“輸入2”和“機箱”中，借助4毫米的插座旋緊終端。輸出：尾部的4毫米插座。配備一個(gè)插在終端上的插座。

Connectors
Input 1. EM low thermal emf terminals.Screw terminals with 4mm sockets for 'Input 2' and 'Case'. Outputs. 4mm socketsat rear. Plug on terminal cover provided.

儀表
105毫米鏡面表盤(pán)，刻度為10-0-10以及3-0-3。

Meter
105mm mirror scale calibrated 10-0-10, and3-0-3.

電源
內部可置換電池，滿(mǎn)充電情況下可以運行50小時(shí)。主干線(xiàn)充電器在16小時(shí)內為電池充滿(mǎn)電，并在儀器關(guān)閉時(shí)或20小時(shí)后使用。電源要求為240V或者110V，50Hz或60Hz�？蓮耐獠�、低噪音和電源中對電池進(jìn)行充電。最低電壓：20V。電池容量：1.2AH。外部充電器必須為交流電源。

Power Supply
Internal chargeable batteries, giving more than50 hours operation from a full charge. Mains powered charger fully charges thebatteries in 16 hours with the instrument switched off or 20 hours when in use.Power required 240V or 110V. 50Hz or 60Hz. 5VA. There is an alternative inputto charge the batteries from an external, low noise, current source. Minimumvoltage. 20V. Battery capacity. 1.2AH. NB. External charger must be acurrent source.

規格
深度： 314毫米 (12.4英寸)
深度： 322毫米(12.7英寸)
高度： 179毫米 (7英寸) 包括折疊腳。

Dimensions
Width. 314mm (12.4")
Depth. 322mm (12.7")
Height. 179mm (7") Including folded feet.

重量
12千克 (26.5磅)

Weight
12Kg (26.5lbs)