USB ports

The engineer wanted to know what should be the minimum rating of the bench power supply for a Buck application with 5V at the input and 3.3V of output, delivering 1A of load current. I think his question initially arose because he was trying to make a small converter powered off a USB port for driving a peripheral device. He was worried how the current limit of the USB port was going to affect the load current he could draw. 

The actual mode of connection between instrument and computer varies depending on the type of signal generated and the design of the instrument. The connection can be made via a serial port, a parallel port, or a USB port. The electronic circuitry required is built into the instrument s internal readout electronics or into an external box used for conditioning the instrument s output signal. In some cases, the instrument will not operate without the computer connection and is switched on and off as the computer is switched on and off. In other cases, the entire computer is built into the instrument. 

The wired receiver system was retired when the RF system was adopted for use campus-wide. The RF system currently used on the author s campus uses a small receiver unit (about the size of a box of chalk) that plugs in to the USB port via a wire. A new version of the RF receiver, which resembles a USB flash drive in size and appearance, is now available. The RF receiver does not have to be set up so as to allow the students to aim their clickers at it, but it does seem that the best results are obtained when the receiver is pointed toward the students, with no obstructions such as books blocking the receiver. 

Most computers built after 1997 have one or two flat ports in place of one DB-9 serial port. These ports are Universal Serial Bus (USB) ports and they are used for connecting multiple (up to 127) peripherals to one computer through a single port (and use of multi-port peripheral hubs ). USB supports data transfer rates as high as 1.5MBps. Additionally, USB cables can be a maximum length of 5 meters. 

Through the use of daisy-chaining and USB hubs, a single USB port can support (theoretically) 127 devices. The USB can also moves data much faster than traditional devices do—up to 12MBps (megabytes per second). 

The only real concern you might have when installing a USB device is overloading the chain. While the specifications state that 127 devices can be connected, those devices will all be competing for that 12MBps bus, and performance will suffer. This is why most modern computers come with two USB ports—it helps to split the workload. 

When connecting USB peripherals, you must connect them either directly to one of the USB ports on the PC or to a USB hub that is connected to one of those USB ports. Hubs can be chained together to provide multiple USB connections. Although you can connect up to 127 devices, it is impractical in reality. Most computers with will support around 12 USB devices. 

With the PC powered on, connect the USB cable from a digital camera to an open USB port, either on a hub or a USB port on the back of the computer. Windows Plug and Play will recognize that there is a new device attached and will automatically start the Add New Hardware Wizard. 

You re using your USB port for your scanner. What is the preferred method for swapping your scanner with a previously configured digital camera ... 

D. None of the above. Digital cameras will not work on a USB port. 

A counter for measuring changes of the resonance frequency can be a common device widely used in electronics. The resolution of frequency should be at least 1Hz within Is interval, the upper limit of frequency should be near 50 MHz. An important feature is the possibility to connect to a personal computer to allow on-line monitoring of the affinity interaction the easiest way is through the standard serial (RS 232C) and USB ports, the GPIB option will require a special interface... 

PDQ is a portable photodiode device for simultaneous analysis of up to eight samples (Fig. 3a). It uses commercially available 0.2 ml PCR tubes or 8-well PCR strips. In this machine, light is detected from the bottom of tubes. PDQ can be used in standalone mode or when connected to a PC through a USB-port. Power consumption is low enough for the machine to be run off a car battery if used in a field. PDQ is a low-cost distributed device suitable for point-of-care applications. Dedicated software offers a choice of tests with pre-set parameters (Fig. 3b) and analyses the data giving a final result for each sample at the end of the run, when used in the diagnostic mode (Fig. 3c). 

Figure 1.V24 shows a photograph of a miniature liber-optic spectrometer using a linear CCD array. The optical diagram is similar to that shown in Figure 13-14, except that fiber optics are used to transport the radiation to and from the sample cell. In the version shown, the spectrometer is external to the computer. I he output of the array connects to an analog-to-digiial converter board in the computer. In other models, the spectrometer contains the converter and interfaces K> the computer via a USB port. Such spectrometers are available from about 1800 to about. U(H).

The group data, by one machine to the USB port to PC intelligent gas content prediction system. Run the PC software, set the COM port and baud rate, input to upload data from the instrument category, run the upload menu. PC interface is shown in Figure 3. 

The interface pressure (IP) between the skin and garment was measured using a flexible sensor int ace system (RSscan International). This system was custom made specifically for this project it included a flat, flexible sensor measuring 7.5cm x 3.0cm, consisting of various cells, feeding into a converter unit vdiich in turn plugged into the USB port of the computer on which the software was installed. 

Skin blood flow (SBF) was measured using a laser Doppler blood perfusion monitor (Vasamedics Laserflo Blood Perfusion Monitor BPM ). The monitor was cormected to the computer via the computer s USB port The sensor used to monitor the superficial skin blood flow fed data into the monitor, and this data was collated by a voltage data logger this was then offloaded to the computer s OTLM programme. OTLM recorded the electrical signal produced by the flow of blood in the superficial vessels in the skin, and thus, as for humidity, the units of the raw data were millivolts (mV). 

RFID middleware contributes a major portion of RFID investment. Many vendors supply RFID middleware, and the cost can vary depending upon the capabilities of the middleware. Usually factors that contribute to cost include complexity of the application and the number of places the middleware would be installed. Apart from the middleware, the companies should also consider the cost of edge servers, which are normally deployed in the warehouse, distribution center, or production facility. The edge servers are simple servers, which are connected to the RFID reader using a universal serial bus (USB) port. 

Originally, all CDS were control and evaluation systems of one instrument manufacturer. The aim was to provide a better and more convenient control of the in-house HPLC and GC instruments. As the solutions were always focused on the own instrument hardware, almost every manufacturer uses his own system to connect instruments to the computer hardware. Besides standardized formats such as IEEE488 Bus Waters Agilent), there can be found serial interfaces, later on often USB ports or proprietary connections. In correlation with standardized communication protocols, this can lead to incompatibiUties, why some laboratories have decided to use several CDS each having its particular data system. In order to decrease the effort that arises from training laboratory staff and multiple installations, maintenances, and software validations, companies aim to decrease the number of CDS in their laboratories to a minimum. Having the focus on one CDS helps to define a unique workflow and ensures a consistent documentation of the processes. 

Figure 27.2 USB-to-IDC connector without the IDC or female USB port attached (left) and both parts attached to the fabric substrate (right).

Signals are recorded with a 24 bit- 4 channels dynamic signals analyzer powered by the laptop data acquisition computer s USB port. 

It is possible to warm up the grill before arriving home by connecting to the Internet and attaching an iGrill to a USB port. Recipes can also be downloaded directly from the Internet for the iGrill. 

One current trend in modern analytical instrumentation is to use devices lhat connect to the computer via a USB port (see Table 4-4). The USB standard allows connection of up to 127 different devices in a simple, straightforward manner. C urrently. printers, cameras, disk drives, scanners, webcams, networking components, some data-acquisition systems, and some analytical instruments are available with USB interfaces. Some devices now include a FireWire connection. With these, several devices can be connected in series (daisy-chained) so that only one FireWire port is required for multiple units. Devices that require very high-speed connections, such as the data-acquisition board shown in Figure 4-12b. still require interface lioards that connect directly to the internal computer bus. 

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