Grounding guidelines

Electrostatic discharge damage

Electronic components are sensitive to electrostatic discharge (ESD). Circuitry design and structure determine the degree of sensitivity. Networks built into many integrated circuits provide some protection, but in many cases, ESD contains enough power to alter device parameters or melt silicon junctions.

A discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or microcircuitry. Even if the spark is neither felt nor heard, damage may have occurred.

An electronic device exposed to ESD may not be affected at all and can work perfectly throughout a normal cycle. Or the device may function normally for a while, then degrade in the internal layers, reducing its life expectancy.

CAUTION: To prevent damage to the computer when you are removing or installing internal components, observe these precautions:

Keep components in their electrostatic-safe containers until you are ready to install them.

Use nonmagnetic tools.

Before touching an electronic component, discharge static electricity by using the guidelines described in this section.

Avoid touching pins, leads, and circuitry. Handle electronic components as little as possible.

If you remove a component, place it in an electrostatic-safe container.

The following table shows how humidity affects the electrostatic voltage levels generated by different activities.

CAUTION: A product can be degraded by as little as 700 V.

Typical electrostatic voltage levels

 

 

Relative humidity

 

 

 

 

 

Event

10%

40%

55%

 

 

 

 

Walking across carpet

35,000 V

15,000 V

7,500 V

 

 

 

 

Walking across vinyl floor

12,000 V

5,000 V

3,000 V

 

 

 

 

Motions of bench worker

6,000 V

800 V

400 V

 

 

 

 

Removing DIPS from plastic tube

2,000 V

700 V

400 V

 

 

 

 

Removing DIPS from vinyl tray

11,500 V

4,000 V

2,000 V

 

 

 

 

Removing DIPS from Styrofoam

14,500 V

5,000 V

3,500 V

 

 

 

 

Removing bubble pack from PCB

26,500 V

20,000 V

7,000 V

 

 

 

 

Packing PCBs in foam-lined box

21,000 V

11,000 V

5,000 V

 

 

 

 

50 Chapter 4 Removal and replacement procedures

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HP 4720S, 4520S manual Grounding guidelines, Electrostatic discharge damage
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4720S, 4520S specifications

The HP ProBook 4720s is a well-engineered business laptop that combines performance, durability, and affordability, making it suitable for professionals and small business owners alike. Introduced as part of the HP ProBook series, this model stands out for its robust build quality and essential features tailored to meet the demands of various work environments.

One of the main features of the HP 4720s is its 17.3-inch display. This spacious screen provides a generous workspace for multitasking, with a resolution of 1600 x 900 pixels. The anti-glare technology helps reduce reflections, ensuring that users can work comfortably in different lighting conditions. The large screen also makes it suitable for presentations and sharing visuals with colleagues.

Under the hood, the HP ProBook 4720s is equipped with Intel's second generation Core processors. The inclusion of options such as the Intel Core i5 and i7 provides users with the power necessary for demanding applications while maintaining energy efficiency. With up to 8GB of DDR3 RAM, multitasking is seamless, allowing users to run multiple applications simultaneously without experiencing lag.

Storage options are varied, including traditional hard drives and solid-state drives which offer faster data access speeds. This flexibility ensures that users can choose the configuration that best fits their needs, balancing performance and storage capacity.

In terms of connectivity, the HP 4720s offers a range of ports including USB 2.0 and USB 3.0, HDMI, and Ethernet, providing users with versatile options for connecting peripherals and external displays. The integrated webcam and microphone are essential for video conferencing, essential in today’s remote working environment.

Another characteristic that makes the HP ProBook 4720s stand out is its security features. The optional fingerprint reader and HP’s Client Security software provide enhanced protection for sensitive data. This focus on security is crucial for professionals who handle confidential information.

Moreover, the laptop's design features a sturdy chassis that meets military specifications for durability. This ruggedness is complemented by a spill-resistant keyboard, which enhances its usability in various environments.

Overall, the HP ProBook 4720s embodies a balance of performance, functionality, and durability. Its features cater well to business users seeking a reliable device, making it a commendable choice in the competitive landscape of laptops. Whether for office use or on-the-go productivity, the HP 4720s delivers a solid computing experience.
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