【单选题】
14稳压管的工作是利用伏安特性中的___。
A. 正向特性
B. 反向特性
C. 反向击穿特性
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答案
C
解析
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相关试题
【单选题】
15二极管具有___
A. 正向特性
B. 反向特性
C. 单向导电特性
D. 反向击穿特性
【单选题】
16图中D1-D3为理想二极管,A,B,C灯都相同,试问___灯最亮。
A. A灯
B. B灯
C. C灯
【单选题】
18在单相桥式整流电容滤波电路中,设U2为其输入电压,输出电压的平均值约为___。
A. U0=0.45U2
B. U0=1.2U2
C. U0=0.9U2
D. U0=1.4U2
【单选题】
19在单相桥式整流电路中,设U2为其输入电压,输出电压的平均值约为___。
A. U0=0.45U2
B. U0=1.2U2
C. U0=0.9U2
D. U0=1.4U2
【单选题】
20在半波整流电容滤波电路中,设U2为其输入电压,输出电压的平均值约为___。
A. U0=0.45U2
B. U0=1.2U2
C. U0=0.9U2
D. U0=1.4U2
【单选题】
21在半波整流电路中,设U2为其输入电压,输出电压的平均值约为___。
A. U0=0.45U2
B. U0=1.2U2
C. U0=0.9U2
D. U0=1.4U2
【单选题】
22温度影响了放大电路中的___,从而使静态工作点不稳定。
A. 电阻;
B. 电容;
C. 三极管;
D. 电源。
【单选题】
23用直流电压表测得放大电路中某三极管各极电位分别是2V、6V、2.7V,则三个电极分别是___。
A. [B、C、E]
B. [C、B、E]
C. [E、C、B]
【单选题】
24共射极放大电路的交流输出波形上半周失真时为___
A. 饱和失真
B. 截止失真
C. 交越失真
【单选题】
25三极管的反向电流ICBO是由___组成的。
A. 多数载流子
B. 少数载流子
C. 多数载流子和少数载流子
【单选题】
27如果在NPN型三极管放大电路中测得发射结为正向偏置,集电结也为正向偏置,则此管的工作状态为___
A. 放大状态;
B. 截止状态;
C. 饱和状态;
D. 不能确定。
【单选题】
28在以下三种电路中输入电阻最大的电路是___。
A. 共基放大电路
B. 共集放大电路
C. 共射放大电路
【单选题】
29在以下三种电路中既能放大电流,又能放大电压的电路是___。
A. 共基放大电路
B. 共集放大电路
C. 共射放大电路
【单选题】
30在以下三种电路中输出电阻最小的电路是___;
A. 共基放大电路
B. 共集放大电路
C. 共射放大电路
【单选题】
当PNP型晶体管工作在放大区时,各极电位关系为uC ___uB。
A. >
B. <
C. =
D. ≤
【单选题】
32当PNP型晶体管工作在放大区时,各极电位关系为uB___uE 。
A. >
B. <
C. =
D. ≤
【单选题】
33测得NPN型三极管上各电极对地电位分别为,,,说明此三极管处在___。
A. 放大区
B. 饱和区
C. 截止区
D. 反向击穿区
【单选题】
34若使三极管具有电流放大能力,必须满足的外部条件是___。
A. 发射结正偏、集电结正偏
B. 发射结反偏、集电结反偏
C. 发射结正偏、集电结反偏
D. 发射结反偏、集电结正偏
【单选题】
35在由PNP晶体管组成的基本共射放大电路中,当输入信号为1KHz、5mV的正弦电压时,输出电压波形出现了顶部削平的失真。这种失真是___ 。
A. 饱和失真
B. 截止失真
C. 交越失真
D. 频率失真
【单选题】
36在由PNP晶体管组成的基本共射放大电路中,当输入信号为1KHz、5mV的正弦电压时,输出电压波形出现了底部削平的失真。这种失真是___ 。
A. 饱和失真
B. 截止失真
C. 交越失真
D. 频率失真
【单选题】
37共集电极放大电路中Re的负反馈组态是___。
A. 电压串联负反馈
B. 电流串联负反馈
C. 电压并联负反馈
【单选题】
38为了使放大器带负载能力强,一般引入___负反馈。
A. 电压
B. 电流
C. 串联
【单选题】
41为了提高三极管放大电路的输入电阻,采用___负反馈 i=i1+i2
A. 电流
B. 电压
C. 并联
D. 串联
【单选题】
42为了稳定输出电流,采用___负反馈。
A. 电流
B. 电压
C. 并联
D. 串联
【单选题】
43为了改善放大器的动态性能,应该引入___电路。
A. 直流负反馈
B. 交流负反馈
C. 电压负反馈
D. 电流负反馈
【单选题】
44为了稳定放大器的静态工作点,应该引入___电路。
A. 直流负反馈
B. 交流负反馈
C. 电压负反馈
D. 电流负反馈
【单选题】
45共模抑制比是差分放大电路的一个主要技术指标,它反映放大电路___能力。
A. 放大差模抑制共模
B. 输入电阻高
C. 输出电阻低
【单选题】
46差分放大电路是为了___而设置的。
A. 稳定Au
B. 放大信号
C. 抑制零点漂移
【单选题】
47分析运放的“虚短”是指是___。
A. U-≈U+
B. I-≈I+≈0
C. U0=Ui
D. U-≈U+≈0
【单选题】
48分析运放的“虚断”是指是___。
A. U-≈U+
B. I-≈I+≈0
C. I-≈I+
D. U-≈U+≈0
【单选题】
51两级放大电路,Au1=-40,Au2=-50,若输入电压U1=5mv,则输出电压Uo为 ___
A. -200mv;
B. -250mV;
C. 10V;
D. 100V
【单选题】
52通用型集成运放的输入级多采用___。
A. 共基接法
B. 共集接法
C. 共射接法
D. 差分接法
【单选题】
53理想运放的两个重要性质是___。
A. 虚短与虚地
B. 虚断与虚短
C. 断路与短路
【单选题】
54振荡器的输出信号最初由___而来的。
A. 基本放大器
B. 选频网络
C. 干扰或噪声信号
【单选题】
55产生正弦波自激震荡的稳定条件是___。
A. 引入正反馈
B. |AF|≥1
C. AF=1
【单选题】
56从结构上来看,正弦振荡电路是一个 ___ 。
A. 有输入信号的负反馈放大器;
B. 没有输入信号的带选频网络的正反馈放大器;
C. 没有输入信号的不带选频网络的正反馈放大器。
【单选题】
57对频率稳定度要求较高的振荡器,要采用: ___ 。
A. LC振荡电路;
B. RC振荡电路;
C. RL振荡电路;
D. 石英晶体振荡电路。
【单选题】
58在甲类、乙类、甲乙类放大电路中,其导通角分别为___
A. 小于180 O、180 O、360O
B. 360O、180 O、小于180 O。
C. 180 O、小于180 O、360O
【单选题】
W78XX系和列W79XX系列引脚对应关系为 ___ 。
A. 一致;
B. 1脚与3脚对调,2脚不变;
C. 1、2对调。
【单选题】
60两个β相同的晶体管组成复合管后,其电流放大系数约为 ___ 。
A. β
B. β2
C. 2β
D. 1+β
推荐试题
【单选题】
During the installation of ESXi 6.0, the following error message is reported: Hardware Virtualization is not a feature of the CPU, or is not enabled in the BIOS. Which condition would generate this message? ___
A. LAHF/SAHF is not enabled in the BIOS.
B. NX/XD is not enabled in the BIOS.
C. SSE3 is not enabled in the BIOS.
D. Hyperthreading is not enabled in the BIOS.
【单选题】
An administrator is unable to login to vCenter Server when using the vSphere web client. The administrator successfully accessed vCenter Server using the client earlier the same day. What is the most appropriate first step the administrator should take to resolve this issue? ___
A. Verify the web browser being used has Adobe Flash plugin version 11.5 or later
B. Verify the vCenter Single Sign-On service is running on the vCenter Server
C. Verify the vSphere Web Server service is running on the vCenter Server
D. Verify the administrator has permissions configured in vCenter Server
【单选题】
An administrator has configured an alarm to be notified when a virtual machine meets two conditions: <high virtual CPU> <high active memory consumption> The alarm is malfunctioning and triggering when either condition is met instead of both. What can be done to correct the issue? ___
A. Edit the alarm and select Trigger if ALL of the following conditions are satisfied.
B. Edit the alarm and select Trigger if ANY of the following conditions are satisfied.
C. Create two separate alarms, one for CPU and one for memory.
D. Delete the existing alarm and create a new event based alarm.
【单选题】
What must be enabled to ensure that VM Component Protection (VMCP) works in a High Availability cluster? ___
A. VMware Tools Virtual Machine Communication Interface (VMCI)
B. Fault Tolerance
C. Atomic Test and Set (ATS)
D. All Paths Down (APD) Timeout
【单选题】
An administrator wants to add a web server to an existing multi-tier application consisting of three virtual machines: <A web server> <A database server An application server> The web server should be added to the application when the primary web server reaches: <70% vCPU utilization> <55% active memory> Which option will achieve this result? ___
A. Create a virtual machine alarm with an action to run a script that starts a new instance of the web server.
B. Create a host cpu and memory alarm with an action to run a script that starts a new instance of the webserver.
C. Configure HA application monitoring for the web server and set it to trigger deployment of a new instance of the web server.
D. Configure Fault Tolerance on the virtual machine and leave the secondary machine disabled until needed.
【单选题】
An administrator has an application that requires connection directly to PCI devices through a virtual machine. What is a limitation of this configuration? ___
A. Devices must be reserved for PCI passthrough on at least one host on which the virtual machine will run.
B. Snapshots are not supported with DirectPath I/O passthrough devices.
C. A maximum of 18 PCI vSphere
D. irectPath devices can be added to a virtual machine.
【单选题】
The vSphere administrator is configuring directory services for an ESXi host: What should the vSphere administrator do to configure the host to use CAM services? ___
A. Check the Use vSphere Authentication Proxy checkbox.
B. Set Select Directory Service Type to CAM services.
C. Specify CAM$ for the
D. omain.
【单选题】
Which statement is true regarding the licensing of vCenter Server? ___
A. The license for vCenter Server must be provided at the time of installation.
B. Changing the license assigned to vCenter Server requires a restart of the vCenter Server service.
C. Virtual machines can still be powered on if the vCenter Server license expires.
D. Licensing for a single vCenter Server installation is determined by the number of managed virtual machines.
【单选题】
When configuring vSphere Replication for a virtual machine, what is the lowest Recovery Point Objective (RPO) that can be selected? ___
A. 1 min
B. 5 min
C. 10 min
D. 15min
【单选题】
A developer needs to create a multi-tier development stack for a home lab. Which vSphere product will support the architecture required for the least software cost? ___
A. vSphere Hypervisor
B. vSphere Essentials
C. VMware Player
D. VMware Workstation
【单选题】
An administrator is installing Windows into a virtual machine. The DVD has been mounted on the Host and configured for the virtual machine as shown in the Exhibit. Based on the exhibit, when the virtual machine is booted, why would it attempt to search for a PXE server? ___
A. The CD/DVD device is not connected.
B. The ISO is in the incorrect storage location.
C. The OS minimum requirements have not been met.
D. The CD/DVD device is not set to Client Device.
【单选题】
What component must be installed prior to deploying a vCenter Server in vSphere 6.x? ___
A. vCenter Identity Services
B. Platform Services Controller
C. vCenter Single Sign-On
D. Client Integration Plug-In
【单选题】
What is a valid plug-in status for a plug-in that has been added to a vSphere client? ___
A. Disabled
B. Unknown
C. Stopped
D. Installed
【单选题】
Users of an application are reporting performance issues. The following performance values are observed in the vSphere Web Client: <Host CPU utilization is 90%> <Virtual Machine memory utilization is consistently greater than 90% CPU Ready values are higher than 20%> What could be the cause of the application performance issue? ___
A. The host is lacking the CPU resources required to meet the demand.
B. The host is lacking the memory resources required to meet the demand.
C. The virtual machine is lacking the CPU resources required to meet the demand.
D. The virtual machine is lacking the memory resources required to meet the demand.
【单选题】
An administrator creates an ESXi cluster using vSphere Auto Deploy. The ESXi hosts are configured to get a management IP address from a DHCP server. The administrator needs to troubleshoot the management network on one of the hosts. Which DCUI option should the administrator use to renew the DHCP lease? ___
A. Restart Management Network
B. Restore Network Settings
C. Test Management Network
D. Configure Management Network
【单选题】
An administrator is re-provisioning an ESXi host and moving it to another datacenter. Which DCUI option should the administrator use to revert the system configuration to the default settings? ___
A. Reset System Configuration
B. Rebuild Default System Configuration
C. Revert System Configuration
D. Renew Default System Configuration
【单选题】
An administrator has just completed installing an ESXi 6.x host, but doesn't know what address has been configured. Where is the ESXi host IP address configured? ___
A. RVC console
B. Direct Console User Interface
C. vSphere Web Client
D. vSphere Client
【单选题】
When is it possible to place a VMFS5 datastore in maintenance mode? ___
A. When it is a member of a Storage DRS cluster
B. When it is a member of Virtual SAN cluster
C. When it is a member of a multi-extent datastore
D. When it is a member of a Virtual Volume
【单选题】
Immediately after installing ESXi, an administrator observes that the Configure Lockdown Mode option is grayed out in the Direct Console User Interface (DCUI). What is the most likely explanation? ___
A. The host has not yet been added to a vCenter Server.
B. The BIOS on the host does not have NX/XD enabled.
C. The ESXi host is running in evaluation mode.
D. The host requires a reboot before this feature is available.
【单选题】
Immediately after installing ESXi, an administrator observes that the Configure Lockdown Mode option is grayed out in the Direct Console User Interface (DCUI). What is the most likely explanation? ___
A. The host has not yet been added to a vCenter Server.
B. The BIOS on the host does not have NX/XD enabled.
C. The ESXi host is running in evaluation mode.
D. The host requires a reboot before this feature is available.
【单选题】
Which Single Sign-On deployment mode should an administrator use for two 6.x vCenter Servers configured with linked mode? ___
A. Basic Single Sign-On with vCenter Server Heartbeat
B. Multisite Single Sign-On
C. Basic Single Sign-On
D. Single Sign-On with Linked Mode
【单选题】
What is required when changing a virtual machine name using the vSphere Web Client? ___
A. Verify connectivity to the ESXi host where the virtual machine is running and its inventory list is accessible.
B. Verify in which datastore the virtual machine resides and that you have access and its inventory list is accessible.
C. Verify that virtual machine files are stored in the same datastore and can be accessed in the datastore browser list.
D. Verify the virtual machine is not running in Fault Tolerant mode and that it is not in a Distributed Resource Scheduler cluster.
【单选题】
An administrator deploys vRealize Operations into a vSphere 6.x environment. After the deployment, the administrator notices that badges are not appearing. What is a likely cause of this behavior? ___
A. Badges do not appear until you register vRealize Operations with vCenter Server.
B. Badges do not appear until you register a vCenter Server in vRealize Operations.
C. The vRealize Operations appliance needs to be redeployed.
D. The vCenter Server appliance needs to be redeployed.
【单选题】
How are ports scaled on vSphere Standard Switches (vSS)? ___
A. Ports on a vSS can be dynamically scaled up and down.
B. Ports on a vSS can only be statically scaled up or down.
C. Ports on a vSS can only be dynamically scaled down.
D. Ports on a vSS can only be dynamically scaled up.
【单选题】
A High Availability (HA) cluster is configured to respond to a given number of host failures. The cluster contains virtual machines configured with these settings: VM1 has a 1GHz CPU reservation and no Memory reservation VM2 has a 2GHz CPU reservation and no Memory reservation VM3 has no CPU reservation and no Memory reservation . Given this information, what is the correct slot size for the cluster? ___
A. The CPU Reservation should be set to 32MHz and the memory reservation should be set to 32MB plus memory overhead.
B. The CPU reservation should be set to 1 GHz and the memory reservation should be set to 0MB plus memory overhead.
C. The CPU reservation should be set to 2 GHz, and the memory reservation should be set to 0MB plus the virtual machine memory overhead.
D. The CPU reservation should be set to 2 GHz, and the memory reservation should be set to 32MB, plus the virtual machine memory overhead.
【单选题】
An administrator is planning a vSphere infrastructure with the following specific networking requirements: <The ability to shape inbound (RX) traffic> <Support for Private VLANs (PVLANs)> <Support for LLDP (Link Layer Discovery Protocol)>. What is the minimum vSphere Edition that will support these requirements? ___
A. vSphere Essentials Plus
B. vSphere Standard
C. vSphere Enterprise
D. vSphere
E. nterprise Plus
【单选题】
When you add an ESXi 6.x host to a new Cluster, which vSphere object owns the CPU and Memory resources of the hosts? ___
A. vCenter Server
B. Datacenter
C. Cluster
D. Host
【单选题】
A user is trying to retrieve objects from a SharePoint server and finds the request is taking an excessive amount of time. An administrator tries to isolate the issue and notes the following: Application performance is poor when compared to virtual machines on other hosts. Performance improves when the virtual machine is moved to another host. The virtual machine encounters higher than expected CPU %Ready times. What conclusion can be reached regarding the performance issues for this virtual machine? ___
A. Host Power Management is directly impacting virtual machine performance.
B. The virtual machine has a large number of snapshots.
C. The Path Selection Policy for the storage device is set differently on the affected host.
D. Network I/O control is configured for the portgroup.
【单选题】
A virtual machine template is accidently removed from the vCenter Server Inventory. Which method would be used to recover the template back into the environment?___
A. Use the datastore browser to locate the template, then right click and add the .vmtx file to inventory.
B. Use the datastore browser to locate the template, then right click and add the .vmx file to inventory.
C. Using the Managed Object Browser and adding the template from the ManagedObjectReference:GuestFileManager object.
D. Using the Managed Object Browser and adding the template from the ManagedObjectReference:VirtualDiskManager object.
【单选题】
A vSphere administrator needs to backup a virtual machine that has a Microsoft SQL Server Database installed. Which solution allows for an application quiesce to occur during backup?___
A. VMware vCenter Converter
B. VMware vCenter Site Recovery Manager
C. VMware vSphere Replication
D. VMware vSphere Data Protection Advanced
【单选题】
An administrator is migrating a virtual machine from a Test cluster to a Production cluster. The two environments do not have any shared storage. What is the easiest way to accomplish this task? ___
A. Perform a Storage vMotion.
B. Perform a regular vMotion.
C. Perform a Virtual to Virtual migration.
D. Perform a backup and restore using VMware Data Protection.
【单选题】
An administrator must determine an appropriate backup solution, given these conditions: 50 of the virtual machines are in a resource pool named Finance. 50 of the virtual machines are in a resource pool named QA. Which solution allows an administrator the ability to backup 100 virtual machines? ___
A. Use Snapshot Manager on the vCenter Server to backup the virtual machines.
B. Use the VMware Consolidated Backup (vcb) tool on the ESXi Host to backup the virtual machines.
C. Use the VMware Data Recovery (VDR) Appliance on the vCenter Server to backup the virtual machines.
D. Use the VMware Data Protection (VDP) Appliance on one of the
E. SXi Hosts to backup the virtual machines.
【单选题】
What is a benefit of using Enhanced vMotion Compatibility for an environment? ___
A. EVC masks CPU features to allow compatibility between hosts that are dissimilar.
B. EVC allows for cross platform vMotion to occur.
C. EVC enables Long
D. istance vMotion.
【单选题】
How many Link Aggregation Groups (LAGs) can be configured on a vSphere 6.x Distributed Switch? ___
A. 64
B. 96
C. 128
D. 256
【单选题】
How many Link Aggregation Groups (LAGs) can be configured on a vSphere 6.x Distributed Switch? ___
A. 64
B. 96
C. 128
D. 256
【单选题】
An administrator needs to verify that vMotion operations can be performed in a vSphere data center.What round trip time (RTT) latency is the maximum value that will allow vMotion operations to succeed? ___
A. 50ms RTT
B. 100ms RTT
C. 150ms RTT
D. 200ms RTT
【单选题】
A storage administrator has reported that full utilization of all bandwidth from an ESXi 6.x host is not being seen. In troubleshooting the issue, the Adapter details are shown in the Exhibit. Based on the exhibit, what is cause of the issue? ___
A. The array is not setup to use the correct multipathing policy.
B. There are no virtual machines on the ESXi host.
C. Not all links are used because a path is disabled.
D. Another path needs to be configured.
【单选题】
An administrator is migrating a powered-on virtual machine, as shown in the exhibit. Which option should be selected to perform a Storage vMotion of the VM? ___
A. Change storage only
B. Change VM compute resource only
C. Change both compute resource and storage, changing the compute resource first.
D. Change both compute resource and storage, changing the storage resource first.
【单选题】
An administrator is attempting to enable Storage I/O Control on a datastore, but it is failing. What is the likely reason for this failure? ___
A. The host is connected to a datastore is running on ESX 4.0.
B. The host is connected to a Fibre Channel storage array.
C. The datastore has multiple extents.
D. The datastore is managed by a single vCenter Server.
【单选题】
A mission-critical virtual machine built on vSphere 4.1 needs to be moved to an ESXi 6.x host.Which virtual hardware version is needed to move the virtual machine without upgrading? ___
A. 6
B. 7
C. 10
D. 11