If using a card such as the Model 7013 Relay Switch card, ch. 2 is normally energized.
如果采用类似7013型继电器开关卡这样的开关卡，通道2通常是加激励的。
Switch card specifications typically specify relay drive current rather than coil power.
开关卡的技术指标通常给出继电器的驱动电流值，而不是线圈功率。
The connections to the switch card itself represent another source of thermally generated voltages.
开关卡的连接本身也是另一个热电电压源。
Information about making connections to a particular switch card can be found in the card's manual.
关于连接特定开关卡的信息，请参阅开关卡的手册。
Most switch CARDS have jumpers that can be removed to disconnect the card output from the backplane.
大多数开关卡都有跳线，可以通过拆下跳线将插卡的输出从背板断开。
To measure the offset of a switch card, connect the output of the card to a pico ammeter or electrometer.
若要测量开关卡的偏移电流，请将卡的输出连接到一台皮安计或静电计。
This may require using a high current switch card for sourcing and a low voltage switch card for measuring.
这就可能需要利用一个大电流开关卡来提供电流，一个小电压开关卡用于测量。
The offset current specification of the switch card should be as low as possible for switching low current.
对于切换小电流来说，开关卡的偏移电流指标应该尽可能小。
To ensure proper shielding, choose a switch card with shielded connectors, such as coax or triax connectors.
为确保合适的屏蔽，请选择带有屏蔽连接器的开关卡，例如同轴或同轴三柱连接器。
If cleaning the board becomes necessary, follow the instructions in the manual provided with the switch card.
如果有必要清洁开关卡，请严格按照随开关卡提供的手册中的说明执行。
This section describes microwave switch types, RF switch card specifications, and RF switch design considerations.
本节介绍微波开关的类型、RF开关卡技术指标，以及设计RF开关时的注意事项。
To prevent leakage current on the switch card, take special care when handling to prevent degradation of performance.
为预防开关卡上的漏流，在防止性能劣化时要特别注意。
Factors that affect the maximum current through the switch card include the traces on the board, the connectors, and the relays.
影响通过开关卡的最大电流的因素包括电路板上的走线、连接器和继电器。
Switch card specifications are usually stated with a specific application in mind, such as low current or high voltage switching.
开关卡的技术指标通常是由特定的应用决定的，例如小电流或高电压切换。
The contact potential or thermoelectric offset voltage is the key specification of a switch card designed for low voltage switching.
接触电势或热电效应偏移电压是设计用于低压切换的开关卡的关键技术指标。
End-of-life is generally considered to be the time when the total channel resistance exceeds the specifications for the switch card.
当总通道电阻超过了开关卡的指标时，则认为使用寿命终了。
Contact potential is affected by changes in ambient temperature as well as by the presence of temperature gradients across a switch card.
接触电势受环境温度变化以及开关卡上温度梯度的影响。
"Maximum signal levels" refers to the highest levels of voltage, current, and power that can be switched without damaging the switch card.
“最大信号电平”是指能够切换但又不会损坏开关卡的电压、电流和功率的最大值。
Such effects can be reduced by thoughtful placement of a switch card within a switch mainframe and of a switch system within an equipment rack.
在开关主机中精心配置开关卡，以及在设备机柜中精心配置开关系统，都可以减小这种影响。
Also, shielded cabling, such as coax or triax, should be used to make connections from the high impedance devices or signal sources to the switch card.
此外，应该使用屏蔽电缆，例如同轴或同轴三芯，连接高阻装置或信号源和开关卡。
Isolated relays, such as those used in the Model 7013 relay Switch Card, can be used to control certain test system requirements, such as the conveyor.
隔离继电器，例如7013行继电器开关卡中使用的继电器，可被用来控制特定的测试系统要求，例如传送带。
The highest voltage a switch card can withstand reliably is the maximum volt age specification, which is determined primarily by the relay specification.
开关卡能够可靠承受的最高电压即为最大电压指标，它主要是由继电器的技术指标决定的。
To prevent damage to the switch card, verify that the product of the maximum current and maximum voltage does not exceed the power rating of the switch card.
为防止损坏开关卡，需验证最大电流和最大电压的乘积没有超过开关卡的功率额定值。
It is generally unnecessary to verify the isolation capacitance on a switch card, because the capacitance is a mechanical function and should not change over time.
由于电容属于一种机械性能，并且不应随时间发生变化，所有通常必须要验证开关卡上的隔离电容。
It is useful to understand the meaning and characteristics of coil power, but one generally does not have to consider this specification when selecting a switch card.
了解线圈功率的含义及其特性是非常有益的，但是人们在选择开关卡并非必须要考虑该技术指标。
If a particular switch card with no backplane connection is installed in a slot of the mainframe, it will be electrically isolated from other CARDS installed in the mainframe.
如果将没有背板连接的特殊开关卡安装到主机的某个插槽，那么它和主机中安装的其它插卡则是电气隔离的。
The thermoelectric offset voltage due to the switch card and the interconnecting cable may be compensated for by using a short-circuited channel to establish a zero reference.
由于开关卡和互连电缆引起的热电效应偏移电压可采用一个短路通道来建立一个零参考，从而进行补偿。
The switch card specifications can be helpful in determining the degree of uncertainty due to the switch card, but use only the specifications relevant to the particular application in error analysis.
开关卡的技术指标可帮助确定开关卡引起的不确定度，但是在进行误差分析时需要只能采用与特定应用相关的技术指标。
When you start playing a game or watching a HD video, it will automatically switch to the powerful nVidia or ATi graphics card.
当用户玩游戏或观看高清视频时，切换使用高效显卡。
When you start playing a game or watching a HD video, it will automatically switch to the powerful nVidia or ATi graphics card.
当用户玩游戏或观看高清视频时，切换使用高效显卡。
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