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Electrical Safety
Published in W. David Yates, Safety Professional’s Reference and Study Guide, 2020
When an electrical system is not grounded properly, a hazard exists. The most common Occupational Safety and Health Administration electrical violation is improper grounding of equipment and circuitry. The metal parts of an electrical wiring system that we touch (switch plates, ceiling light fixtures, conduit, etc.) should be grounded and at 0 V. If the system is not grounded properly, these parts may become energized. Metal parts of motors, appliances, or electronics that are plugged into improperly grounded circuits may be energized. When a circuit is not grounded properly, a hazard exists because unwanted voltage cannot be safely eliminated. If there is no safe path to ground for fault currents, exposed metal parts in damaged appliances can become energized.10
Switches
Published in Kevin Robinson, Practical Audio Electronics, 2020
These switches have no moving parts. They can be particularly useful in outdoors applications and in harsh environments, as they are generally robust and can be sealed effectively against water and other contaminants. Resistive touch switches are often used in outdoors locations on elevator buttons, ticket dispensers, and vending machines. Capacitive touch switch technology is the basis of many touch screens on mobile phones, tablets, and computers. Piezo touch switches can be actuated while wearing gloves as they do not require skin contact in order to work. This is in contrast to resistive, and to some extent capacitive styles, which generally do require contact or very close proximity to actuate. Other variations on these basic approaches also exist involving various methods for detecting touch or proximity. The present section is not intended to be in any way a detailed review of this class of switch. The intention is simply to flag the existence and primary features of such switches. These devices tend to be more expensive than traditional mechanical switches and will rarely be encountered in audio electronics applications, although homemade variants can be useful and interesting.
Electrical Safety
Published in W. David Yates, Safety Professional’s, 2015
When an electrical system is not grounded properly, a hazard exists. The most common Occupational Safety and Health Administration electrical violation is improper grounding of equipment and circuitry. The metal parts of an electrical wiring system that we touch (switch plates, ceiling light fixtures, conduit, etc.) should be grounded and at 0 V. If the system is not grounded properly, these parts may become energized. Metal parts of motors, appliances, or electronics that are plugged into improperly grounded circuits may be energized. When a circuit is not grounded properly, a hazard exists because unwanted voltage cannot be safely eliminated. If there is no safe path to ground for fault currents, exposed metal parts in damaged appliances can become energized.10
Effect of adapted motorized ride-on toy use on developmental skills, quality of life, and driving competency in nonambulatory children age 9–60 months
Published in Assistive Technology, 2023
Kara Arps, Nancy Darr, Jamie Katz
The AMTs were commercially available, Lil’ Rider Cruisin’ Coupe battery operated cars. One participant used a Dynacraft BMW 6 V series battery operated car. AMTs were adapted using PVC pipe, kickboards, pool noodles, and VelcroTM to provide postural support based on each child’s physical abilities. Electrical modifications were performed to eliminate foot pedal activation by substituting a doorbell mounted between 2 pieces of plexi-glass or a commercially available touch switch (Sparkfun Big Dome Pushbutton) to activate the device by hand. The switch was mounted in the center of the steering wheel for most participants, but switch placement was modified as needed to meet each child’s specific needs. At week 10, AMTs of three participants were adapted to provide a modified steering system. PVC pipe was attached to the switch with VelcroTM and then bolted into the sides of the steering wheel to secure. AMTs were adapted for the participants who demonstrated interest in steering and the capacity to consistently stop the AMT to avoid obstacles. See Figure 1 for example, of AMT design.